diff --git a/python/ebook_search/answer.py b/python/ebook_search/answer.py
index 4b85b21..ba7f6aa 100644
--- a/python/ebook_search/answer.py
+++ b/python/ebook_search/answer.py
@@ -8,13 +8,20 @@ from typing import TYPE_CHECKING
 from python.ebook_search.llm_interface import request_chat_completion
 
 if TYPE_CHECKING:
+    import httpx
+
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.search import SearchResult
 
 logger = logging.getLogger(__name__)
 
 
-def answer_query(query: str, results: list[SearchResult], config: EbookSearchConfig) -> str:
+async def answer_query(
+    client: httpx.AsyncClient,
+    query: str,
+    results: list[SearchResult],
+    config: EbookSearchConfig,
+) -> str:
     """Answer a question using only retrieved chunks."""
     if not config.answer_enabled:
         logger.info("ebook_answer_skipped_disabled")
@@ -35,7 +42,8 @@ def answer_query(query: str, results: list[SearchResult], config: EbookSearchCon
         f"[{index}] {result.source_title}{' - ' + result.chapter_title if result.chapter_title else ''}\n{result.text}"
         for index, result in enumerate(results, start=1)
     )
-    content = request_chat_completion(
+    content = await request_chat_completion(
+        client,
         config,
         [
             {
diff --git a/python/ebook_search/api/bm25_tasks.py b/python/ebook_search/api/bm25_tasks.py
index ff24b85..3477b6c 100644
--- a/python/ebook_search/api/bm25_tasks.py
+++ b/python/ebook_search/api/bm25_tasks.py
@@ -1,18 +1,22 @@
-"""Background BM25 refresh tasks for the web app."""
+"""Background BM25 refresh tasks for the web app.
+
+The refresh is scheduled on the event loop instead of a thread because the async psycopg
+driver only works from the loop; a bare thread cannot open a session on the async engine.
+"""
 
 from __future__ import annotations
 
+import asyncio
 import logging
-from threading import Timer
 from typing import TYPE_CHECKING
 
-from sqlalchemy.orm import Session
+from sqlalchemy.ext.asyncio import AsyncSession
 
 from python.ebook_search.bm25_corpus import load_bm25_corpus, refresh_bm25_corpus
 
 if TYPE_CHECKING:
     from fastapi import FastAPI
-    from sqlalchemy.engine import Engine
+    from sqlalchemy.ext.asyncio import AsyncEngine
 
     from python.ebook_search.config import EbookSearchConfig
 
@@ -20,15 +24,18 @@ logger = logging.getLogger(__name__)
 
 
 def schedule_bm25_refresh(app: FastAPI) -> None:
-    """Schedule a delayed BM25 corpus refresh, replacing any pending refresh."""
-    existing_timer = getattr(app.state, "bm25_refresh_timer", None)
-    if existing_timer is not None:
-        existing_timer.cancel()
+    """Schedule a delayed BM25 corpus refresh, replacing any pending refresh.
 
-    timer = Timer(app.state.config.bm25_refresh_delay_seconds, refresh_bm25_for_app, args=(app,))
-    timer.daemon = True
-    timer.start()
-    app.state.bm25_refresh_timer = timer
+    Only called from route handlers, so a running event loop is guaranteed.
+    """
+    cancel_bm25_refresh(app)
+
+    loop = asyncio.get_running_loop()
+
+    def start_refresh() -> None:
+        app.state.bm25_refresh_task = loop.create_task(refresh_bm25_for_app(app))
+
+    app.state.bm25_refresh_timer = loop.call_later(app.state.config.bm25_refresh_delay_seconds, start_refresh)
     logger.info(
         "ebook_bm25_refresh_scheduled delay_seconds=%s",
         app.state.config.bm25_refresh_delay_seconds,
@@ -36,25 +43,31 @@ def schedule_bm25_refresh(app: FastAPI) -> None:
 
 
 def cancel_bm25_refresh(app: FastAPI) -> None:
-    """Cancel any pending BM25 corpus refresh."""
+    """Cancel any pending BM25 corpus refresh timer and in-flight refresh task."""
     existing_timer = getattr(app.state, "bm25_refresh_timer", None)
     if existing_timer is not None:
         existing_timer.cancel()
         app.state.bm25_refresh_timer = None
         logger.info("ebook_bm25_refresh_cancelled")
 
+    existing_task = getattr(app.state, "bm25_refresh_task", None)
+    if existing_task is not None:
+        if not existing_task.done():
+            existing_task.cancel()
+        app.state.bm25_refresh_task = None
 
-def refresh_bm25_for_app(app: FastAPI) -> None:
+
+async def refresh_bm25_for_app(app: FastAPI) -> None:
     """Refresh the BM25 corpus using the app engine and config."""
     try:
-        refresh_bm25_for_engine(app.state.engine, app.state.config)
+        await refresh_bm25_for_engine(app.state.engine, app.state.config)
     except Exception:
         logger.exception("ebook_bm25_refresh_failed")
 
 
-def refresh_bm25_for_engine(engine: Engine, config: EbookSearchConfig) -> None:
-    """Refresh the BM25 corpus using a SQLAlchemy engine."""
-    with Session(engine) as session:
-        refresh_bm25_corpus(session, config)
+async def refresh_bm25_for_engine(engine: AsyncEngine, config: EbookSearchConfig) -> None:
+    """Refresh the BM25 corpus using an async SQLAlchemy engine."""
+    async with AsyncSession(engine) as session:
+        await refresh_bm25_corpus(session, config)
     load_bm25_corpus.cache_clear()
     logger.info("ebook_bm25_corpus_cache_cleared_after_refresh")
diff --git a/python/ebook_search/api/dependencies.py b/python/ebook_search/api/dependencies.py
index e5a89fa..508dfd7 100644
--- a/python/ebook_search/api/dependencies.py
+++ b/python/ebook_search/api/dependencies.py
@@ -4,8 +4,9 @@ from __future__ import annotations
 
 from typing import Annotated
 
+import httpx
 from fastapi import Depends, Request
-from sqlalchemy.engine import Engine
+from sqlalchemy.ext.asyncio import AsyncEngine
 
 from python.ebook_search.config import EbookSearchConfig
 
@@ -15,10 +16,16 @@ def get_config(request: Request) -> EbookSearchConfig:
     return request.app.state.config
 
 
-def get_engine(request: Request) -> Engine:
+def get_engine(request: Request) -> AsyncEngine:
     """Get the database engine from app state."""
     return request.app.state.engine
 
 
+def get_http_client(request: Request) -> httpx.AsyncClient:
+    """Get the shared LLM HTTP client from app state."""
+    return request.app.state.http_client
+
+
 AppConfig = Annotated[EbookSearchConfig, Depends(get_config)]
-AppEngine = Annotated[Engine, Depends(get_engine)]
+AppEngine = Annotated[AsyncEngine, Depends(get_engine)]
+AppHttpClient = Annotated[httpx.AsyncClient, Depends(get_http_client)]
diff --git a/python/ebook_search/api/judge_tasks.py b/python/ebook_search/api/judge_tasks.py
new file mode 100644
index 0000000..7bc07b0
--- /dev/null
+++ b/python/ebook_search/api/judge_tasks.py
@@ -0,0 +1,131 @@
+"""Background phrase-judging tasks for the web app.
+
+Judging a book sends one LLM request per candidate phrase, which can take minutes, so it must
+not run inside the request where it would block the UI. Judgments run as async FastAPI
+background tasks, awaited on the event loop after the response is sent, and are tracked per
+book in app state so a second judge request for a book that is already being judged is
+rejected instead of doubling the work.
+
+State is loop-confined: every read and mutation happens on the event loop (async route
+handlers and async background tasks) and no critical section contains an ``await``, so each
+mutation is atomic per loop iteration and no locking is needed.
+"""
+
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING
+
+from python.ebook_search.protected_phrases.judge_ngrams import judge_candidate_phrases_for_books
+
+if TYPE_CHECKING:
+    from fastapi import BackgroundTasks, FastAPI
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class JudgeTaskState:
+    """Running book judgments and last outcome messages, keyed by book id."""
+
+    running_book_ids: set[int] = field(default_factory=set)
+    outcome_messages: dict[int, str] = field(default_factory=dict)
+
+
+def get_judge_task_state(app: FastAPI) -> JudgeTaskState:
+    """Return the app's judge task state, creating it on first use.
+
+    Args:
+        app (FastAPI): App whose state holds the judge task registry.
+
+    Returns:
+        JudgeTaskState: The shared judge task state for this app.
+    """
+    state = getattr(app.state, "judge_tasks", None)
+    if state is None:
+        state = JudgeTaskState()
+        app.state.judge_tasks = state
+    return state
+
+
+def start_book_phrase_judgment(app: FastAPI, background_tasks: BackgroundTasks, source_id: int) -> bool:
+    """Queue judging of one book's candidate phrases as a FastAPI background task.
+
+    The book is claimed before the response returns, so a repeated judge request cannot queue
+    a second run while one is pending or running.
+
+    Args:
+        app (FastAPI): App supplying the engine, config, and judge task state.
+        background_tasks (BackgroundTasks): Request's background tasks to queue the judgment on.
+        source_id (int): Book to judge candidates for.
+
+    Returns:
+        bool: True when a judgment was queued, False when one is already running for this book.
+    """
+    state = get_judge_task_state(app)
+    if source_id in state.running_book_ids:
+        logger.info("ebook_book_phrase_judgment_already_running source_id=%s", source_id)
+        return False
+    state.running_book_ids.add(source_id)
+    state.outcome_messages.pop(source_id, None)
+    background_tasks.add_task(judge_book_phrases_for_app, app, source_id)
+    logger.info("ebook_book_phrase_judgment_queued source_id=%s", source_id)
+    return True
+
+
+async def judge_book_phrases_for_app(app: FastAPI, source_id: int) -> None:
+    """Judge one book using the app engine and config, recording the outcome message.
+
+    Args:
+        app (FastAPI): App supplying the engine, config, and judge task state.
+        source_id (int): Book to judge candidates for.
+    """
+    state = get_judge_task_state(app)
+    try:
+        result = await judge_candidate_phrases_for_books(app.state.engine, app.state.config, source_ids=[source_id])
+        logger.info(
+            "ebook_book_phrase_judgment_complete source_id=%s judged=%s protected=%s mentions=%s failed=%s",
+            source_id,
+            result.candidates_judged,
+            result.protected_phrases,
+            result.phrase_mentions,
+            result.books_failed,
+        )
+        if result.books_failed:
+            message = "Judging failed; see server logs for details"
+        else:
+            message = (
+                f"Judged {result.candidates_judged} candidates; {result.protected_phrases} protected phrases promoted"
+            )
+    except Exception:
+        logger.exception("ebook_book_phrase_judgment_task_failed source_id=%s", source_id)
+        message = "Judging failed; see server logs for details"
+    state.running_book_ids.discard(source_id)
+    state.outcome_messages[source_id] = message
+
+
+def is_judging_book(app: FastAPI, source_id: int) -> bool:
+    """Report whether a judgment is currently queued or running for one book.
+
+    Args:
+        app (FastAPI): App supplying the judge task state.
+        source_id (int): Book to check.
+
+    Returns:
+        bool: True while the book's judgment is pending or running.
+    """
+    return source_id in get_judge_task_state(app).running_book_ids
+
+
+def pop_book_judgment_outcome(app: FastAPI, source_id: int) -> str | None:
+    """Return and clear the outcome message from one book's last finished judgment.
+
+    Args:
+        app (FastAPI): App supplying the judge task state.
+        source_id (int): Book to fetch the outcome for.
+
+    Returns:
+        str | None: The outcome message, or None when there is nothing new to report.
+    """
+    return get_judge_task_state(app).outcome_messages.pop(source_id, None)
diff --git a/python/ebook_search/api/main.py b/python/ebook_search/api/main.py
index 87e3316..4b286d1 100644
--- a/python/ebook_search/api/main.py
+++ b/python/ebook_search/api/main.py
@@ -6,11 +6,12 @@ import logging
 from contextlib import asynccontextmanager
 from typing import TYPE_CHECKING, Annotated
 
+import httpx
 import typer
 import uvicorn
 from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
-from sqlalchemy.orm import Session
+from sqlalchemy.ext.asyncio import AsyncSession
 
 from python.common import configure_logger
 from python.ebook_search.api.bm25_tasks import cancel_bm25_refresh
@@ -18,8 +19,9 @@ from python.ebook_search.api.routes import admin_router, health_router, page_rou
 from python.ebook_search.api.web import STATIC_DIR
 from python.ebook_search.bm25_corpus import ensure_bm25_corpus
 from python.ebook_search.config import load_config
+from python.ebook_search.protected_phrases.pool import shutdown_extraction_pool
 from python.fastapi_tools import ZstdMiddleware
-from python.orm.common import get_postgres_engine
+from python.orm.common import get_async_postgres_engine
 
 if TYPE_CHECKING:
     from collections.abc import AsyncIterator
@@ -48,15 +50,24 @@ async def lifespan(app: FastAPI) -> AsyncIterator[None]:
     )
     if not config.library_paths:
         logger.warning("ebook_search_no_library_paths_configured")
-    app.state.engine = get_postgres_engine(name="RICHIE", vector_engine=True)
-    with Session(app.state.engine) as session:
-        ensure_bm25_corpus(session, config)
+    # Concurrent phrase judging opens one session per book worker on this engine, so size the pool
+    # to cover those plus headroom for ordinary web requests.
+    app.state.engine = get_async_postgres_engine(
+        name="RICHIE",
+        vector_engine=True,
+        pool_size=config.phrase_judge_book_workers + 10,
+    )
+    app.state.http_client = httpx.AsyncClient()
+    async with AsyncSession(app.state.engine, expire_on_commit=False) as session:
+        await ensure_bm25_corpus(session, config)
     try:
         yield
     finally:
         logger.info("ebook_search_shutdown")
         cancel_bm25_refresh(app)
-        app.state.engine.dispose()
+        shutdown_extraction_pool()
+        await app.state.http_client.aclose()
+        await app.state.engine.dispose()
 
 
 def create_app() -> FastAPI:
diff --git a/python/ebook_search/api/routes/admin.py b/python/ebook_search/api/routes/admin.py
index 737ec74..6860609 100644
--- a/python/ebook_search/api/routes/admin.py
+++ b/python/ebook_search/api/routes/admin.py
@@ -8,15 +8,18 @@ from fastapi import APIRouter, Request
 from fastapi.responses import HTMLResponse
 
 from python.ebook_search.api.bm25_tasks import schedule_bm25_refresh
-from python.ebook_search.api.dependencies import (
-    AppConfig,  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
+from python.ebook_search.api.dependencies import (  # noqa: TC001 FastAPI resolves these annotated dependencies at runtime
+    AppConfig,
+    AppEngine,
+    AppHttpClient,
 )
 from python.ebook_search.api.web import templates
 from python.ebook_search.embeddings import embed_missing_chunks, embedding_model_stats
 from python.ebook_search.ingest import ingest_configured_paths
 from python.ebook_search.protected_phrases.generate_ngrams import generate_candidate_phrases_for_books
 from python.ebook_search.protected_phrases.judge_ngrams import judge_candidate_phrases_for_books
-from python.fastapi_tools import DbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
+from python.ebook_search.protected_phrases.store import book_ids_pending_first_judgment, corpus_phrase_stats
+from python.fastapi_tools import AsyncDbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
 
 logger = logging.getLogger(__name__)
 
@@ -24,19 +27,29 @@ router = APIRouter(prefix="/admin")
 
 
 @router.get("", response_class=HTMLResponse)
-def admin(request: Request, config: AppConfig, session: DbSession) -> HTMLResponse:
+async def admin(request: Request, config: AppConfig, session: AsyncDbSession) -> HTMLResponse:
     """Render the admin page."""
-    stats = embedding_model_stats(session)
-    logger.info("ebook_admin_page_loaded models=%s", len(stats))
-    return templates.TemplateResponse(request, "admin.html", {"config": config, "stats": stats})
+    stats = await embedding_model_stats(session)
+    phrase_stats = await corpus_phrase_stats(session)
+    logger.info(
+        "ebook_admin_page_loaded models=%s candidate_phrases=%s protected_phrases=%s",
+        len(stats),
+        phrase_stats.candidate_phrases,
+        phrase_stats.protected_phrases,
+    )
+    return templates.TemplateResponse(
+        request,
+        "admin.html",
+        {"config": config, "stats": stats, "phrase_stats": phrase_stats},
+    )
 
 
 @router.post("/scan", response_class=HTMLResponse)
-def scan_library(request: Request, config: AppConfig, session: DbSession) -> HTMLResponse:
+async def scan_library(request: Request, config: AppConfig, session: AsyncDbSession) -> HTMLResponse:
     """Scan configured library paths for EPUB changes."""
     try:
-        count = ingest_configured_paths(session, config)
-        session.commit()
+        count = await ingest_configured_paths(session, config)
+        await session.commit()
     except Exception as error:
         logger.exception("ebook_admin_scan_failed")
         return templates.TemplateResponse(request, "partials/error.html", {"message": str(error)}, status_code=500)
@@ -47,48 +60,119 @@ def scan_library(request: Request, config: AppConfig, session: DbSession) -> HTM
     return templates.TemplateResponse(request, "partials/admin_status.html", {"message": f"Indexed {count} EPUBs"})
 
 
-@router.post("/generate-ngrams", response_class=HTMLResponse)
-def generate_ngrams(request: Request, config: AppConfig, session: DbSession) -> HTMLResponse:
-    """Generate candidate n-grams for indexed books without LLM judging."""
+@router.post("/phrases/generate-all", response_class=HTMLResponse)
+async def generate_all_phrases(request: Request, config: AppConfig, session: AsyncDbSession) -> HTMLResponse:
+    """Regenerate candidate phrases for every indexed book without LLM judging."""
+    return await run_phrase_generation(request, config, session, only_missing=False)
+
+
+@router.post("/phrases/generate-missing", response_class=HTMLResponse)
+async def generate_missing_phrases(request: Request, config: AppConfig, session: AsyncDbSession) -> HTMLResponse:
+    """Generate candidate phrases only for books that have none yet."""
+    return await run_phrase_generation(request, config, session, only_missing=True)
+
+
+async def run_phrase_generation(
+    request: Request,
+    config: AppConfig,
+    session: AsyncDbSession,
+    *,
+    only_missing: bool,
+) -> HTMLResponse:
+    """Run candidate phrase generation and render the outcome as an admin status partial.
+
+    Args:
+        request (Request): Current request, for template rendering.
+        config (AppConfig): Runtime phrase-tuning settings.
+        session (AsyncDbSession): Active database session.
+        only_missing (bool): Only generate for books without candidates instead of every book.
+
+    Returns:
+        HTMLResponse: Status partial describing the generation outcome.
+    """
     try:
-        result = generate_candidate_phrases_for_books(session, config)
-        session.commit()
+        result = await generate_candidate_phrases_for_books(session, config, only_missing=only_missing)
+        await session.commit()
     except Exception as error:
-        session.rollback()
-        logger.exception("ebook_admin_generate_ngrams_failed")
+        await session.rollback()
+        logger.exception("ebook_admin_generate_phrases_failed only_missing=%s", only_missing)
         return templates.TemplateResponse(request, "partials/error.html", {"message": str(error)}, status_code=500)
 
     logger.info(
-        "ebook_admin_generate_ngrams_complete books_seen=%s books_built=%s candidates=%s",
+        "ebook_admin_generate_phrases_complete only_missing=%s books_seen=%s books_built=%s candidates=%s",
+        only_missing,
         result.books_seen,
         result.books_built,
         result.candidate_phrases,
     )
+    if only_missing and result.books_seen == 0:
+        return templates.TemplateResponse(
+            request,
+            "partials/admin_status.html",
+            {"message": "All books already have candidate phrases"},
+        )
     return templates.TemplateResponse(
         request,
         "partials/admin_status.html",
         {
             "message": (
-                f"Generated n-grams for {result.books_built} of {result.books_seen} books; "
+                f"Generated phrases for {result.books_built} of {result.books_seen} books; "
                 f"{result.candidate_phrases} candidates stored"
             )
         },
     )
 
 
-@router.post("/judge-ngrams", response_class=HTMLResponse)
-def judge_ngrams(request: Request, config: AppConfig, session: DbSession) -> HTMLResponse:
-    """Judge stored candidate n-grams and promote accepted protected phrases."""
+@router.post("/phrases/judge-all", response_class=HTMLResponse)
+async def judge_all_phrases(request: Request, engine: AppEngine, config: AppConfig) -> HTMLResponse:
+    """Judge unjudged candidate phrases across every indexed book."""
+    return await run_phrase_judgment(request, engine, config, source_ids=None)
+
+
+@router.post("/phrases/judge-missing", response_class=HTMLResponse)
+async def judge_missing_phrases(
+    request: Request,
+    engine: AppEngine,
+    config: AppConfig,
+    session: AsyncDbSession,
+) -> HTMLResponse:
+    """Judge candidate phrases only for books where judging has never run."""
+    source_ids = await book_ids_pending_first_judgment(session)
+    if not source_ids:
+        return templates.TemplateResponse(
+            request,
+            "partials/admin_status.html",
+            {"message": "All books with candidate phrases have been judged"},
+        )
+    return await run_phrase_judgment(request, engine, config, source_ids=source_ids)
+
+
+async def run_phrase_judgment(
+    request: Request,
+    engine: AppEngine,
+    config: AppConfig,
+    *,
+    source_ids: list[int] | None,
+) -> HTMLResponse:
+    """Run LLM judging for candidate phrases and render the outcome as an admin status partial.
+
+    Args:
+        request (Request): Current request, for template rendering.
+        engine (AppEngine): Engine used to open per-book judging sessions.
+        config (AppConfig): Runtime phrase-tuning settings.
+        source_ids (list[int] | None): Books to judge; ``None`` judges every indexed book.
+
+    Returns:
+        HTMLResponse: Status partial describing the judging outcome.
+    """
     try:
-        result = judge_candidate_phrases_for_books(session, config)
-        session.commit()
+        result = await judge_candidate_phrases_for_books(engine, config, source_ids=source_ids)
     except Exception as error:
-        session.rollback()
-        logger.exception("ebook_admin_judge_ngrams_failed")
+        logger.exception("ebook_admin_judge_phrases_failed")
         return templates.TemplateResponse(request, "partials/error.html", {"message": str(error)}, status_code=500)
 
     logger.info(
-        "ebook_admin_judge_ngrams_complete books_seen=%s books_judged=%s books_failed=%s candidates_judged=%s "
+        "ebook_admin_judge_phrases_complete books_seen=%s books_judged=%s books_failed=%s candidates_judged=%s "
         "protected=%s mentions=%s",
         result.books_seen,
         result.books_judged,
@@ -112,11 +196,16 @@ def judge_ngrams(request: Request, config: AppConfig, session: DbSession) -> HTM
 
 
 @router.post("/embed-missing", response_class=HTMLResponse)
-def embed_missing(request: Request, config: AppConfig, session: DbSession) -> HTMLResponse:
+async def embed_missing(
+    request: Request,
+    config: AppConfig,
+    session: AsyncDbSession,
+    client: AppHttpClient,
+) -> HTMLResponse:
     """Embed chunks missing vectors for the configured model."""
     try:
-        count = embed_missing_chunks(session, config)
-        session.commit()
+        count = await embed_missing_chunks(session, client, config)
+        await session.commit()
     except Exception as error:
         logger.exception("ebook_admin_embed_missing_failed")
         return templates.TemplateResponse(request, "partials/error.html", {"message": str(error)}, status_code=500)
@@ -130,16 +219,21 @@ def embed_missing(request: Request, config: AppConfig, session: DbSession) -> HT
 
 
 @router.post("/embed-all", response_class=HTMLResponse)
-def embed_all(request: Request, config: AppConfig, session: DbSession) -> HTMLResponse:
+async def embed_all(
+    request: Request,
+    config: AppConfig,
+    session: AsyncDbSession,
+    client: AppHttpClient,
+) -> HTMLResponse:
     """Embed all chunks missing vectors in fixed-size batches."""
     total = 0
     batches = 0
     try:
         while True:
-            count = embed_missing_chunks(session, config)
+            count = await embed_missing_chunks(session, client, config)
             if count == 0:
                 break
-            session.commit()
+            await session.commit()
             total += count
             batches += 1
             logger.info(
diff --git a/python/ebook_search/api/routes/health.py b/python/ebook_search/api/routes/health.py
index fb7c097..f5726fd 100644
--- a/python/ebook_search/api/routes/health.py
+++ b/python/ebook_search/api/routes/health.py
@@ -11,15 +11,17 @@ from fastapi.responses import JSONResponse
 from sqlalchemy import literal, select
 from sqlalchemy.exc import SQLAlchemyError
 
-from python.ebook_search.api.dependencies import (
-    AppConfig,  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
+from python.ebook_search.api.dependencies import (  # noqa: TC001 FastAPI resolves these annotated dependencies at runtime
+    AppConfig,
+    AppHttpClient,
 )
 from python.ebook_search.bm25_corpus import bm25_index_exists, bm25_index_path, read_bm25_manifest
 from python.ebook_search.llm_interface import check_chat_endpoint, check_embedding_endpoint
-from python.fastapi_tools import DbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
+from python.fastapi_tools import AsyncDbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
 
 if TYPE_CHECKING:
-    from sqlalchemy.orm import Session
+    import httpx
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
 
@@ -29,17 +31,17 @@ router = APIRouter()
 
 
 @router.get("/health")
-def health() -> dict[str, str]:
+async def health() -> dict[str, str]:
     """Liveness probe that returns ok without touching dependencies."""
     return {"status": "ok"}
 
 
 @router.get("/ready")
-def ready(config: AppConfig, session: DbSession) -> JSONResponse:
+async def ready(config: AppConfig, session: AsyncDbSession, client: AppHttpClient) -> JSONResponse:
     """Readiness probe reporting database, embedding endpoint, and BM25 index status."""
-    database_ok = check_database(session)
-    embedding_ok = check_embedding_endpoint(config)
-    chat_status = chat_endpoint_status(config)
+    database_ok = await check_database(session)
+    embedding_ok = await check_embedding_endpoint(client, config)
+    chat_status = await chat_endpoint_status(client, config)
     bm25_status = check_bm25_status(config)
 
     checks = {
@@ -69,17 +71,17 @@ def ready(config: AppConfig, session: DbSession) -> JSONResponse:
     return JSONResponse(content={"status": status, "checks": checks}, status_code=status_code)
 
 
-def chat_endpoint_status(config: EbookSearchConfig) -> str:
+async def chat_endpoint_status(client: httpx.AsyncClient, config: EbookSearchConfig) -> str:
     """Return the answering chat endpoint status, or disabled when answers are off."""
     if not config.answer_enabled:
         return "disabled"
-    return "ok" if check_chat_endpoint(config) else "fail"
+    return "ok" if await check_chat_endpoint(client, config) else "fail"
 
 
-def check_database(session: Session) -> bool:
+async def check_database(session: AsyncSession) -> bool:
     """Return whether the database answers a trivial query."""
     try:
-        session.execute(select(literal(1)))
+        await session.execute(select(literal(1)))
     except SQLAlchemyError as error:
         logger.warning("ebook_ready_database_unavailable error=%s", error)
         return False
diff --git a/python/ebook_search/api/routes/page.py b/python/ebook_search/api/routes/page.py
index 4608f39..47858ee 100644
--- a/python/ebook_search/api/routes/page.py
+++ b/python/ebook_search/api/routes/page.py
@@ -3,18 +3,23 @@
 from __future__ import annotations
 
 import logging
+from typing import TYPE_CHECKING
 
-from fastapi import APIRouter, HTTPException, Request
+from fastapi import APIRouter, BackgroundTasks, HTTPException, Request
 from fastapi.responses import HTMLResponse, RedirectResponse
 from sqlalchemy import func, select
 
 from python.ebook_search.api.dependencies import (
     AppConfig,  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
 )
+from python.ebook_search.api.judge_tasks import is_judging_book, pop_book_judgment_outcome, start_book_phrase_judgment
 from python.ebook_search.api.web import templates
 from python.ebook_search.protected_phrases.generate_ngrams import recalculate_candidate_phrases_for_book
-from python.fastapi_tools import DbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
-from python.orm.richie import EbookCandidatePhrase, EbookProtectedPhrase, EbookSource
+from python.fastapi_tools import AsyncDbSession  # noqa: TC001 FastAPI resolves this annotated dependency at runtime
+from python.orm.richie import EbookCandidatePhrase, EbookChapter, EbookChunk, EbookProtectedPhrase, EbookSource
+
+if TYPE_CHECKING:
+    from sqlalchemy.ext.asyncio import AsyncSession
 
 logger = logging.getLogger(__name__)
 
@@ -22,30 +27,41 @@ router = APIRouter()
 
 
 @router.get("/", response_class=HTMLResponse)
-def index(request: Request, config: AppConfig) -> HTMLResponse:
+async def index(request: Request, config: AppConfig) -> HTMLResponse:
     """Render the search page."""
     return templates.TemplateResponse(request, "search.html", {"config": config})
 
 
 @router.get("/books", response_class=HTMLResponse)
-def books(request: Request, session: DbSession) -> HTMLResponse:
+async def books(request: Request, session: AsyncDbSession) -> HTMLResponse:
     """Render the indexed books page."""
-    sources = list(session.scalars(select(EbookSource).order_by(EbookSource.title)).all())
+    sources = list((await session.scalars(select(EbookSource).order_by(EbookSource.title))).all())
     logger.info("ebook_books_page_loaded count=%s", len(sources))
     return templates.TemplateResponse(request, "books.html", {"sources": sources})
 
 
-def get_candidate_count(session: DbSession, book_id: int) -> int:
+async def get_chapter_count(session: AsyncSession, book_id: int) -> int:
+    """Return the number of indexed chapters for one book."""
+    return await session.scalar(select(func.count(EbookChapter.id)).where(EbookChapter.source_id == book_id)) or 0
+
+
+async def get_chunk_count(session: AsyncSession, book_id: int) -> int:
+    """Return the number of indexed chunks for one book."""
+    return await session.scalar(select(func.count(EbookChunk.id)).where(EbookChunk.source_id == book_id)) or 0
+
+
+async def get_candidate_count(session: AsyncSession, book_id: int) -> int:
     """Return the number of indexed candidates for one book."""
     return (
-        session.scalar(select(func.count(EbookCandidatePhrase.id)).where(EbookCandidatePhrase.book_id == book_id)) or 0
+        await session.scalar(select(func.count(EbookCandidatePhrase.id)).where(EbookCandidatePhrase.book_id == book_id))
+        or 0
     )
 
 
-def get_judged_candidate_count(session: DbSession, book_id: int) -> int:
+async def get_judged_candidate_count(session: AsyncSession, book_id: int) -> int:
     """Return the number of judged candidates for one book."""
     return (
-        session.scalar(
+        await session.scalar(
             select(func.count(EbookCandidatePhrase.id)).where(
                 EbookCandidatePhrase.book_id == book_id,
                 EbookCandidatePhrase.llm_judged.is_(True),
@@ -55,17 +71,18 @@ def get_judged_candidate_count(session: DbSession, book_id: int) -> int:
     )
 
 
-def get_protected_count(session: DbSession, book_id: int) -> int:
+async def get_protected_count(session: AsyncSession, book_id: int) -> int:
     """Return the number of protected phrases for one book."""
     return (
-        session.scalar(select(func.count(EbookProtectedPhrase.id)).where(EbookProtectedPhrase.book_id == book_id)) or 0
+        await session.scalar(select(func.count(EbookProtectedPhrase.id)).where(EbookProtectedPhrase.book_id == book_id))
+        or 0
     )
 
 
-def get_candidates(session: DbSession, book_id: int) -> list[EbookCandidatePhrase]:
+async def get_candidates(session: AsyncSession, book_id: int) -> list[EbookCandidatePhrase]:
     """Return the indexed candidates for one book."""
     return list(
-        session.scalars(
+        await session.scalars(
             select(EbookCandidatePhrase)
             .where(EbookCandidatePhrase.book_id == book_id)
             .order_by(EbookCandidatePhrase.candidate_score.desc())
@@ -74,10 +91,10 @@ def get_candidates(session: DbSession, book_id: int) -> list[EbookCandidatePhras
     )
 
 
-def get_protected_phrases(session: DbSession, book_id: int) -> list[EbookProtectedPhrase]:
+async def get_protected_phrases(session: AsyncSession, book_id: int) -> list[EbookProtectedPhrase]:
     """Return the protected phrases for one book."""
     return list(
-        session.scalars(
+        await session.scalars(
             select(EbookProtectedPhrase)
             .where(EbookProtectedPhrase.book_id == book_id)
             .order_by(EbookProtectedPhrase.importance.desc())
@@ -87,21 +104,27 @@ def get_protected_phrases(session: DbSession, book_id: int) -> list[EbookProtect
 
 
 @router.get("/books/{source_id}", response_class=HTMLResponse)
-def book_detail(source_id: int, request: Request, session: DbSession) -> HTMLResponse:
+async def book_detail(source_id: int, request: Request, session: AsyncDbSession) -> HTMLResponse:
     """Render details for one indexed book."""
-    source = session.get(EbookSource, source_id)
+    source = await session.get(EbookSource, source_id)
     phrase_status_message = None
     recalculated = request.query_params.get("phrases_recalculated")
     if recalculated is not None:
         phrase_status_message = f"Recalculated phrases; {recalculated} candidates generated"
+    judgment_outcome = pop_book_judgment_outcome(request.app, source_id)
+    if judgment_outcome is not None:
+        phrase_status_message = judgment_outcome
+    judging_in_progress = is_judging_book(request.app, source_id)
+    if judging_in_progress:
+        phrase_status_message = "Judging candidate phrases in the background; refresh to see progress"
     if source is not None:
-        chapter_count = len(source.chapters)
-        chunk_count = len(source.chunks)
-        candidate_count = get_candidate_count(session, source.id)
-        judged_candidate_count = get_judged_candidate_count(session, source.id)
-        protected_count = get_protected_count(session, source.id)
-        candidates = get_candidates(session, source.id)
-        protected_phrases = get_protected_phrases(session, source.id)
+        chapter_count = await get_chapter_count(session, source.id)
+        chunk_count = await get_chunk_count(session, source.id)
+        candidate_count = await get_candidate_count(session, source.id)
+        judged_candidate_count = await get_judged_candidate_count(session, source.id)
+        protected_count = await get_protected_count(session, source.id)
+        candidates = await get_candidates(session, source.id)
+        protected_phrases = await get_protected_phrases(session, source.id)
     else:
         chapter_count = 0
         chunk_count = 0
@@ -129,6 +152,7 @@ def book_detail(source_id: int, request: Request, session: DbSession) -> HTMLRes
             "chapter_count": chapter_count,
             "chunk_count": chunk_count,
             "judged_candidate_count": judged_candidate_count,
+            "judging_in_progress": judging_in_progress,
             "protected_count": protected_count,
             "protected_phrases": protected_phrases,
             "phrase_status_message": phrase_status_message,
@@ -138,13 +162,13 @@ def book_detail(source_id: int, request: Request, session: DbSession) -> HTMLRes
 
 
 @router.post("/books/{source_id}/recalculate-phrases")
-def recalculate_book_phrases(source_id: int, config: AppConfig, session: DbSession) -> RedirectResponse:
+async def recalculate_book_phrases(source_id: int, config: AppConfig, session: AsyncDbSession) -> RedirectResponse:
     """Clear and regenerate candidate phrases for one indexed book."""
-    source = session.get(EbookSource, source_id)
+    source = await session.get(EbookSource, source_id)
     if source is None:
         raise HTTPException(status_code=404, detail="Book not found")
 
-    result = recalculate_candidate_phrases_for_book(session, source, config)
+    result = await recalculate_candidate_phrases_for_book(session, source, config, use_process_pool=True)
     logger.info(
         "ebook_book_phrase_recalculation_complete source_id=%s candidates=%s deleted_candidates=%s "
         "deleted_protected=%s deleted_aliases=%s deleted_mentions=%s",
@@ -159,3 +183,20 @@ def recalculate_book_phrases(source_id: int, config: AppConfig, session: DbSessi
         url=f"/books/{source_id}?phrases_recalculated={result.candidate_phrases}",
         status_code=303,
     )
+
+
+@router.post("/books/{source_id}/judge-phrases")
+async def judge_book_phrases(
+    source_id: int,
+    request: Request,
+    background_tasks: BackgroundTasks,
+    session: AsyncDbSession,
+) -> RedirectResponse:
+    """Queue background judging of one book's candidate phrases and return immediately."""
+    source = await session.get(EbookSource, source_id)
+    if source is None:
+        raise HTTPException(status_code=404, detail="Book not found")
+
+    started = start_book_phrase_judgment(request.app, background_tasks, source.id)
+    logger.info("ebook_book_phrase_judgment_requested source_id=%s started=%s", source_id, started)
+    return RedirectResponse(url=f"/books/{source_id}", status_code=303)
diff --git a/python/ebook_search/api/routes/search.py b/python/ebook_search/api/routes/search.py
index 6c7f8a6..0cc95b4 100644
--- a/python/ebook_search/api/routes/search.py
+++ b/python/ebook_search/api/routes/search.py
@@ -14,6 +14,7 @@ from python.ebook_search.answer import answer_query
 from python.ebook_search.api.dependencies import (  # noqa: TC001 FastAPI resolves these annotated dependencies at runtime
     AppConfig,
     AppEngine,
+    AppHttpClient,
 )
 from python.ebook_search.api.web import templates
 from python.ebook_search.guardrails import (
@@ -26,6 +27,8 @@ from python.ebook_search.search import SearchResponse, search_ebooks
 from python.ebook_search.timing import runtime_step_from_start
 
 if TYPE_CHECKING:
+    import httpx
+
     from python.ebook_search.config import EbookSearchConfig
 
 logger = logging.getLogger(__name__)
@@ -33,7 +36,8 @@ logger = logging.getLogger(__name__)
 router = APIRouter()
 
 
-def build_answer(
+async def build_answer(
+    client: httpx.AsyncClient,
     query: str,
     response: SearchResponse,
     config: EbookSearchConfig,
@@ -56,7 +60,7 @@ def build_answer(
         return answer, True, None
 
     try:
-        answer = answer_query(query, response.results, config)
+        answer = await answer_query(client, query, response.results, config)
     except RuntimeError as error:
         logger.warning("ebook_answer_request_failed_falling_back error=%s", error)
         return "Answer generation failed. Source chunks are still shown below.", False, None
@@ -74,18 +78,20 @@ def build_answer(
 
 
 @router.post("/search", response_class=HTMLResponse)
-def search(
+async def search(
     request: Request,
     config: AppConfig,
     engine: AppEngine,
+    client: AppHttpClient,
     query: Annotated[str, Form()],
     rerank: Annotated[str | None, Form()] = None,
     phrase_matching: Annotated[str | None, Form()] = None,
 ) -> HTMLResponse:
     """Run a search and render HTMX results."""
     try:
-        response = search_ebooks(
+        response = await search_ebooks(
             engine,
+            client,
             query,
             config,
             rerank=rerank == "true",
@@ -96,7 +102,7 @@ def search(
         return templates.TemplateResponse(request, "partials/error.html", {"message": str(error)}, status_code=500)
 
     answer_start = perf_counter()
-    answer, low_confidence, citation_report = build_answer(query, response, config)
+    answer, low_confidence, citation_report = await build_answer(client, query, response, config)
     answer_step_name = "Answer generation" if config.answer_enabled else "Answer skipped"
     response = replace(
         response,
diff --git a/python/ebook_search/api/templates/admin.html b/python/ebook_search/api/templates/admin.html
index cd2dacc..512da3a 100644
--- a/python/ebook_search/api/templates/admin.html
+++ b/python/ebook_search/api/templates/admin.html
@@ -8,37 +8,25 @@ head %}
   <form hx-post="/admin/scan" hx-target="#admin-status" hx-swap="innerHTML">
     <button type="submit">Scan</button>
   </form>
-  <form
-    hx-post="/admin/generate-ngrams"
-    hx-target="#admin-status"
-    hx-swap="innerHTML"
-  >
-    <button type="submit">Generate n-grams</button>
-  </form>
-  <form
-    hx-post="/admin/judge-ngrams"
-    hx-target="#admin-status"
-    hx-swap="innerHTML"
-  >
-    <button type="submit">Judge n-grams</button>
-  </form>
-  <form
-    hx-post="/admin/embed-missing"
-    hx-target="#admin-status"
-    hx-swap="innerHTML"
-  >
-    <button type="submit">Embed</button>
-  </form>
-  <form
-    hx-post="/admin/embed-all"
-    hx-target="#admin-status"
-    hx-swap="innerHTML"
-  >
-    <button type="submit">Embed all</button>
-  </form>
 </section>
 <section>
   <h2>Embeddings</h2>
+  <section class="actions">
+    <form
+      hx-post="/admin/embed-missing"
+      hx-target="#admin-status"
+      hx-swap="innerHTML"
+    >
+      <button type="submit">Embed</button>
+    </form>
+    <form
+      hx-post="/admin/embed-all"
+      hx-target="#admin-status"
+      hx-swap="innerHTML"
+    >
+      <button type="submit">Embed all</button>
+    </form>
+  </section>
   <table>
     <thead>
       <tr>
@@ -62,4 +50,61 @@ head %}
     </tbody>
   </table>
 </section>
+<section>
+  <h2>Protected phrases</h2>
+  <section class="actions">
+    <form
+      hx-post="/admin/phrases/generate-all"
+      hx-target="#admin-status"
+      hx-swap="innerHTML"
+    >
+      <button type="submit">Regenerate all phrases</button>
+    </form>
+    <form
+      hx-post="/admin/phrases/generate-missing"
+      hx-target="#admin-status"
+      hx-swap="innerHTML"
+    >
+      <button type="submit">Add missing phrases</button>
+    </form>
+    <form
+      hx-post="/admin/phrases/judge-all"
+      hx-target="#admin-status"
+      hx-swap="innerHTML"
+    >
+      <button type="submit">Judge all phrases</button>
+    </form>
+    <form
+      hx-post="/admin/phrases/judge-missing"
+      hx-target="#admin-status"
+      hx-swap="innerHTML"
+    >
+      <button type="submit">Judge missing phrases</button>
+    </form>
+  </section>
+  <table>
+    <thead>
+      <tr>
+        <th>Candidates</th>
+        <th>Judged</th>
+        <th>Unjudged</th>
+        <th>Protected</th>
+        <th>Books indexed</th>
+        <th>Books generated</th>
+        <th>Books fully judged</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr>
+        <td>{{ phrase_stats.candidate_phrases }}</td>
+        <td>{{ phrase_stats.judged_candidates }}</td>
+        <td>{{ phrase_stats.unjudged_candidates }}</td>
+        <td>{{ phrase_stats.protected_phrases }}</td>
+        <td>{{ phrase_stats.total_books }}</td>
+        <td>{{ phrase_stats.books_with_candidates }}</td>
+        <td>{{ phrase_stats.books_fully_judged }}</td>
+      </tr>
+    </tbody>
+  </table>
+</section>
 {% endblock %}
diff --git a/python/ebook_search/api/templates/book_detail.html b/python/ebook_search/api/templates/book_detail.html
index 1102bec..54fbdcb 100644
--- a/python/ebook_search/api/templates/book_detail.html
+++ b/python/ebook_search/api/templates/book_detail.html
@@ -30,6 +30,15 @@
         >
             <button type="submit">Recalculate phrases</button>
         </form>
+        <form
+            method="post"
+            action="/books/{{ source.id }}/judge-phrases"
+            onsubmit="return confirm('Judge candidate phrases for this book with the LLM?');"
+        >
+            <button type="submit"{% if judging_in_progress %} disabled{% endif %}>
+                {% if judging_in_progress %}Judging&hellip;{% else %}Judge phrases{% endif %}
+            </button>
+        </form>
 
         <section>
             <h2>Candidate n-grams</h2>
diff --git a/python/ebook_search/bm25_corpus.py b/python/ebook_search/bm25_corpus.py
index 0450d64..b0612be 100644
--- a/python/ebook_search/bm25_corpus.py
+++ b/python/ebook_search/bm25_corpus.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import json
 import logging
 import shutil
@@ -17,7 +18,7 @@ from sqlalchemy import func, select, union_all
 from python.orm.richie import EbookChapter, EbookChunk, EbookSource
 
 if TYPE_CHECKING:
-    from sqlalchemy.orm import Session
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
 
@@ -73,14 +74,14 @@ def get_current_bm25_index(index_path: Path) -> Path:
     return index_path
 
 
-def ensure_bm25_corpus(session: Session, config: EbookSearchConfig) -> None:
+async def ensure_bm25_corpus(session: AsyncSession, config: EbookSearchConfig) -> None:
     """Create or refresh the persisted BM25 corpus when it is missing or stale."""
     index_path = bm25_index_path(config)
     manifest = read_bm25_manifest(index_path)
-    db_updated_at = corpus_last_updated_at(session)
+    db_updated_at = await corpus_last_updated_at(session)
     if not bm25_index_exists(index_path, manifest):
         logger.info("ebook_bm25_index_missing path=%s", index_path)
-        refresh_bm25_corpus(session, config, db_updated_at=db_updated_at)
+        await refresh_bm25_corpus(session, config, db_updated_at=db_updated_at)
         return
     if db_updated_at is not None and manifest is not None and manifest.created_at < db_updated_at:
         logger.info(
@@ -89,7 +90,7 @@ def ensure_bm25_corpus(session: Session, config: EbookSearchConfig) -> None:
             manifest.created_at.isoformat(),
             db_updated_at.isoformat(),
         )
-        refresh_bm25_corpus(session, config, db_updated_at=db_updated_at)
+        await refresh_bm25_corpus(session, config, db_updated_at=db_updated_at)
         return
     logger.info(
         "ebook_bm25_index_current path=%s chunks=%s created_at=%s",
@@ -99,21 +100,24 @@ def ensure_bm25_corpus(session: Session, config: EbookSearchConfig) -> None:
     )
 
 
-def refresh_bm25_corpus(
-    session: Session,
+async def refresh_bm25_corpus(
+    session: AsyncSession,
     config: EbookSearchConfig,
     *,
     db_updated_at: datetime | None = None,
 ) -> BM25Manifest:
-    """Rebuild and persist the BM25 corpus from the current database chunks."""
+    """Rebuild and persist the BM25 corpus from the current database chunks.
+
+    The index build is CPU and disk work, so it runs in a worker thread.
+    """
     index_path = bm25_index_path(config)
-    records, texts = fetch_bm25_corpus_records(session)
+    records, texts = await fetch_bm25_corpus_records(session)
     manifest = BM25Manifest(
         created_at=datetime.now(tz=UTC),
-        db_updated_at=db_updated_at if db_updated_at is not None else corpus_last_updated_at(session),
+        db_updated_at=db_updated_at if db_updated_at is not None else await corpus_last_updated_at(session),
         chunk_count=len(records),
     )
-    write_bm25_corpus(index_path, records, texts, manifest)
+    await asyncio.to_thread(write_bm25_corpus, index_path, records, texts, manifest)
     logger.info(
         "ebook_bm25_index_refreshed path=%s chunks=%s created_at=%s",
         index_path,
@@ -164,7 +168,7 @@ def score_bm25_corpus(query: str, corpus: BM25Corpus, *, limit: int) -> list[tup
     return results
 
 
-def fetch_bm25_corpus_records(session: Session) -> tuple[list[dict[str, object]], list[str]]:
+async def fetch_bm25_corpus_records(session: AsyncSession) -> tuple[list[dict[str, object]], list[str]]:
     """Fetch persistable BM25 corpus records and their matching index texts from the database.
 
     search_text is only needed to build the index, so it is returned separately instead of
@@ -188,21 +192,21 @@ def fetch_bm25_corpus_records(session: Session) -> tuple[list[dict[str, object]]
     )
     records: list[dict[str, object]] = []
     texts: list[str] = []
-    for row in session.execute(statement).mappings():
+    for row in (await session.execute(statement)).mappings():
         record = dict(row)
         texts.append(str(record.pop("bm25_text")))
         records.append(record)
     return records, texts
 
 
-def corpus_last_updated_at(session: Session) -> datetime | None:
+async def corpus_last_updated_at(session: AsyncSession) -> datetime | None:
     """Return the latest source/chapter/chunk update timestamp relevant to BM25 text."""
     update_times = union_all(
         select(func.max(EbookSource.updated).label("updated")),
         select(func.max(EbookChapter.updated).label("updated")),
         select(func.max(EbookChunk.updated).label("updated")),
     ).subquery()
-    return session.scalar(select(func.max(update_times.c.updated)))
+    return await session.scalar(select(func.max(update_times.c.updated)))
 
 
 def write_bm25_corpus(
diff --git a/python/ebook_search/config.py b/python/ebook_search/config.py
index 173f07b..687d705 100644
--- a/python/ebook_search/config.py
+++ b/python/ebook_search/config.py
@@ -88,6 +88,9 @@ class EbookSearchConfig(BaseSettings):
     bm25_refresh_delay_seconds: int = 60
     protected_phrase_max_candidates_per_book: int = 5000
     protected_phrase_llm_candidates_per_book: int = 500
+    protected_phrase_extraction_workers: int = 16
+    phrase_judge_book_workers: int = 20
+    phrase_judge_phrase_workers: int = 100
     protected_phrase_confidence_threshold: float = 0.80
     phrase_matching_enabled: bool = True
     phrase_hit_boost: float = 0.25
diff --git a/python/ebook_search/embeddings.py b/python/ebook_search/embeddings.py
index f542e2b..003136e 100644
--- a/python/ebook_search/embeddings.py
+++ b/python/ebook_search/embeddings.py
@@ -23,7 +23,8 @@ logger = logging.getLogger(__name__)
 if TYPE_CHECKING:
     from collections.abc import Sequence
 
-    from sqlalchemy.orm import Session
+    import httpx
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
 
@@ -65,7 +66,11 @@ class EmbeddingModelStats:
         return max(self.total_chunks - self.embedded_chunks, 0)
 
 
-def embed_texts(texts: Sequence[str], config: EbookSearchConfig) -> list[list[float]]:
+async def embed_texts(
+    client: httpx.AsyncClient,
+    texts: Sequence[str],
+    config: EbookSearchConfig,
+) -> list[list[float]]:
     """Embed text with the configured vLLM embedding model."""
     logger.info(
         "ebook_embed_request_start base_url=%s model=%s count=%s",
@@ -73,7 +78,7 @@ def embed_texts(texts: Sequence[str], config: EbookSearchConfig) -> list[list[fl
         config.embedding_model,
         len(texts),
     )
-    vectors = request_embeddings(texts, config)
+    vectors = await request_embeddings(client, texts, config)
     expected_dimension = MODEL_DIMENSIONS[config.embedding_model]
     for vector in vectors:
         if len(vector) != expected_dimension:
@@ -88,28 +93,28 @@ def embed_texts(texts: Sequence[str], config: EbookSearchConfig) -> list[list[fl
     return vectors
 
 
-def embed_query(query: str, config: EbookSearchConfig) -> list[float]:
+async def embed_query(client: httpx.AsyncClient, query: str, config: EbookSearchConfig) -> list[float]:
     """Embed a search query with the Qwen retrieval instruction."""
     instructed_query = f"Instruct: Retrieve relevant passages for the query.\nQuery: {query}"
-    return embed_texts([instructed_query], config)[0]
+    return (await embed_texts(client, [instructed_query], config))[0]
 
 
-def ensure_embedding_models(session: Session) -> None:
+async def ensure_embedding_models(session: AsyncSession) -> None:
     """Ensure supported embedding model rows exist."""
     for name, dimension in MODEL_DIMENSIONS.items():
-        existing = session.scalar(select(EbookEmbeddingModel).where(EbookEmbeddingModel.name == name))
+        existing = await session.scalar(select(EbookEmbeddingModel).where(EbookEmbeddingModel.name == name))
         if existing is None:
             session.add(EbookEmbeddingModel(name=name, dimension=dimension, is_default=name == "qwen3-embedding-0.6b"))
             logger.info("ebook_embedding_model_created model=%s dimension=%s", name, dimension)
-    session.flush()
+    await session.flush()
 
 
-def embedding_model_stats(session: Session) -> list[EmbeddingModelStats]:
+async def embedding_model_stats(session: AsyncSession) -> list[EmbeddingModelStats]:
     """Return embedding coverage counts for every supported model."""
-    total_chunks = session.scalar(select(func.count(EbookChunk.id))) or 0
+    total_chunks = await session.scalar(select(func.count(EbookChunk.id))) or 0
     models = {
         model.name: model
-        for model in session.scalars(
+        for model in await session.scalars(
             select(EbookEmbeddingModel)
             .where(EbookEmbeddingModel.name.in_(MODEL_DIMENSIONS))
             .order_by(EbookEmbeddingModel.name)
@@ -122,7 +127,7 @@ def embedding_model_stats(session: Session) -> list[EmbeddingModelStats]:
         embedded_chunks = 0
         if model is not None:
             table = get_embedding_table(dimension)
-            embedded_chunks = session.scalar(select(func.count(table.id)).where(table.model_id == model.id)) or 0
+            embedded_chunks = await session.scalar(select(func.count(table.id)).where(table.model_id == model.id)) or 0
         stats.append(
             EmbeddingModelStats(
                 model_name=model_name,
@@ -134,10 +139,10 @@ def embedding_model_stats(session: Session) -> list[EmbeddingModelStats]:
     return stats
 
 
-def embed_missing_chunks(session: Session, config: EbookSearchConfig) -> int:
+async def embed_missing_chunks(session: AsyncSession, client: httpx.AsyncClient, config: EbookSearchConfig) -> int:
     """Embed chunks missing embeddings for the configured model."""
-    ensure_embedding_models(session)
-    model = session.scalar(select(EbookEmbeddingModel).where(EbookEmbeddingModel.name == config.embedding_model))
+    await ensure_embedding_models(session)
+    model = await session.scalar(select(EbookEmbeddingModel).where(EbookEmbeddingModel.name == config.embedding_model))
     if model is None:
         supported_models = ", ".join(MODEL_DIMENSIONS)
         msg = f"Unknown embedding model: {config.embedding_model}. Supported models: {supported_models}"
@@ -145,7 +150,7 @@ def embed_missing_chunks(session: Session, config: EbookSearchConfig) -> int:
 
     table = get_embedding_table(model.dimension)
     chunks = list(
-        session.scalars(
+        await session.scalars(
             select(EbookChunk)
             .outerjoin(table, (table.chunk_id == EbookChunk.id) & (table.model_id == model.id))
             .where(table.id.is_(None))
@@ -158,13 +163,13 @@ def embed_missing_chunks(session: Session, config: EbookSearchConfig) -> int:
         return 0
 
     logger.info("ebook_embed_missing_batch_start model=%s count=%s", config.embedding_model, len(chunks))
-    vectors = embed_texts([chunk.text for chunk in chunks], config)
+    vectors = await embed_texts(client, [chunk.text for chunk in chunks], config)
     rows = [
         {"chunk_id": chunk.id, "model_id": model.id, "embedding": vector}
         for chunk, vector in zip(chunks, vectors, strict=True)
     ]
     statement = insert(table).values(rows).on_conflict_do_nothing(index_elements=["chunk_id", "model_id"])
-    session.execute(statement)
-    session.flush()
+    await session.execute(statement)
+    await session.flush()
     logger.info("ebook_embed_missing_batch_complete model=%s count=%s", config.embedding_model, len(rows))
     return len(rows)
diff --git a/python/ebook_search/ingest.py b/python/ebook_search/ingest.py
index b5f9254..51fc801 100644
--- a/python/ebook_search/ingest.py
+++ b/python/ebook_search/ingest.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import hashlib
 import logging
 from dataclasses import dataclass
@@ -21,7 +22,7 @@ DEFAULT_CHUNK_TOKENS = 700
 DEFAULT_CHUNK_OVERLAP = 100
 
 if TYPE_CHECKING:
-    from sqlalchemy.orm import Session
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.epub_parse import ParsedChapter
@@ -73,45 +74,63 @@ def chunk_text(
     return [chunk for chunk in chunks if chunk.text]
 
 
-def ingest_configured_paths(session: Session, config: EbookSearchConfig) -> int:
+def find_library_epubs(library_path: str) -> tuple[Path, list[Path] | None]:
+    """Resolve one configured library path and collect its EPUB files (blocking filesystem walk).
+
+    Returns:
+        tuple[Path, list[Path] | None]: The expanded path and its EPUB files, or ``None`` when
+        the path is neither an EPUB file nor a directory.
+    """
+    path = Path(library_path).expanduser()
+    if path.is_file() and path.suffix.lower() == ".epub":
+        return path, [path]
+    if path.is_dir():
+        return path, sorted(path.rglob("*.epub"))
+    return path, None
+
+
+async def ingest_configured_paths(session: AsyncSession, config: EbookSearchConfig) -> int:
     """Ingest every EPUB found under configured library paths."""
     count = 0
     for library_path in config.library_paths:
-        path = Path(library_path).expanduser()
+        path, epub_paths = await asyncio.to_thread(find_library_epubs, library_path)
         logger.info("ebook_ingest_path_start path=%s", path)
-        if path.is_file() and path.suffix.lower() == ".epub":
-            count += int(ingest_file(session, path, config))
-        elif path.is_dir():
-            for epub_path in sorted(path.rglob("*.epub")):
-                count += int(ingest_file(session, epub_path, config))
-        else:
+        if epub_paths is None:
             logger.warning("ebook_ingest_path_missing path=%s", path)
+            continue
+        for epub_path in epub_paths:
+            count += int(await ingest_file(session, epub_path, config))
     logger.info("ebook_ingest_paths_complete changed_files=%s configured_paths=%s", count, len(config.library_paths))
     return count
 
 
-def ingest_file(session: Session, path: Path, config: EbookSearchConfig) -> bool:
+def resolve_ingest_path(path: Path) -> Path:
+    """Expand and resolve an ingest path (blocking filesystem call)."""
+    return path.expanduser().resolve()
+
+
+async def ingest_file(session: AsyncSession, path: Path, config: EbookSearchConfig) -> bool:
     """Ingest one EPUB file. Return True when the database changed."""
     try:
-        resolved_path = path.expanduser().resolve()
+        resolved_path = await asyncio.to_thread(resolve_ingest_path, path)
         logger.info("ebook_ingest_file_start path=%s", resolved_path)
-        file_hash = sha256_file(resolved_path)
-        existing = find_existing_source(session, resolved_path, file_hash)
+        file_hash = await asyncio.to_thread(sha256_file, resolved_path)
+        existing = await find_existing_source(session, resolved_path, file_hash)
         if existing is not None and existing.file_sha256 == file_hash:
             stat = resolved_path.stat()
             existing.file_path = str(resolved_path)
             existing.file_mtime = datetime.fromtimestamp(stat.st_mtime, tz=UTC)
             existing.file_size = stat.st_size
-            session.flush()
+            await session.flush()
             logger.info("ebook_ingest_file_unchanged source_id=%s path=%s", existing.id, resolved_path)
             return False
         if existing is not None:
             logger.info("ebook_ingest_file_replacing source_id=%s path=%s", existing.id, resolved_path)
-            session.delete(existing)
-            session.flush()
+            await session.delete(existing)
+            await session.flush()
 
         stat = resolved_path.stat()
-        parsed = parse_epub(resolved_path)
+        parsed = await asyncio.to_thread(parse_epub, resolved_path)
         source = EbookSource(
             title=parsed.title,
             author=parsed.author,
@@ -124,7 +143,7 @@ def ingest_file(session: Session, path: Path, config: EbookSearchConfig) -> bool
             file_size=stat.st_size,
         )
         session.add(source)
-        session.flush()
+        await session.flush()
 
         chunk_index = 0
         for spine_index, parsed_chapter in enumerate(parsed.chapters):
@@ -135,11 +154,11 @@ def ingest_file(session: Session, path: Path, config: EbookSearchConfig) -> bool
                 href=parsed_chapter.href,
             )
             session.add(chapter)
-            session.flush()
+            await session.flush()
             chunk_index = add_chapter_chunks(session, source, chapter, parsed_chapter, chunk_index, config)
 
-        session.commit()
-        mention_count = index_chunk_phrase_mentions_for_book(session, source.id, config)
+        await session.commit()
+        mention_count = await index_chunk_phrase_mentions_for_book(session, source.id, config)
         logger.info(
             "ebook_ingest_file_complete source_id=%s path=%s chapters=%s chunks=%s phrase_mentions=%s",
             source.id,
@@ -155,15 +174,15 @@ def ingest_file(session: Session, path: Path, config: EbookSearchConfig) -> bool
         return True
 
 
-def find_existing_source(session: Session, path: Path, file_hash: str) -> EbookSource | None:
+async def find_existing_source(session: AsyncSession, path: Path, file_hash: str) -> EbookSource | None:
     """Find an existing source by canonical path or file hash."""
-    return session.scalar(
+    return await session.scalar(
         select(EbookSource).where(or_(EbookSource.file_path == str(path), EbookSource.file_sha256 == file_hash))
     )
 
 
 def add_chapter_chunks(
-    session: Session,
+    session: AsyncSession,
     source: EbookSource,
     chapter: EbookChapter,
     parsed_chapter: ParsedChapter,
diff --git a/python/ebook_search/llm_interface.py b/python/ebook_search/llm_interface.py
index e573630..0412ee6 100644
--- a/python/ebook_search/llm_interface.py
+++ b/python/ebook_search/llm_interface.py
@@ -22,10 +22,26 @@ def auth_headers(api_key: str) -> dict[str, str]:
     return {"Authorization": f"Bearer {api_key}"}
 
 
-def request_embeddings(texts: Sequence[str], config: EbookSearchConfig) -> list[list[float]]:
-    """Request embeddings from the configured OpenAI-compatible endpoint."""
+async def request_embeddings(
+    client: httpx.AsyncClient,
+    texts: Sequence[str],
+    config: EbookSearchConfig,
+) -> list[list[float]]:
+    """Request embeddings from the configured OpenAI-compatible endpoint.
+
+    Args:
+        client (httpx.AsyncClient): Shared async client for LLM calls.
+        texts (Sequence[str]): Texts to embed.
+        config (EbookSearchConfig): Runtime settings supplying the endpoint, model, and auth.
+
+    Returns:
+        list[list[float]]: One embedding vector per input text.
+
+    Raises:
+        RuntimeError: If the request fails or the response cannot be parsed.
+    """
     try:
-        response = httpx.post(
+        response = await client.post(
             f"{config.embedding_base_url.rstrip('/')}/embeddings",
             headers=auth_headers(config.embedding_api_key),
             json={"model": config.embedding_model, "input": list(texts)},
@@ -44,10 +60,15 @@ def request_embeddings(texts: Sequence[str], config: EbookSearchConfig) -> list[
         raise RuntimeError(msg) from error
 
 
-def check_embedding_endpoint(config: EbookSearchConfig, *, timeout_seconds: float = 5.0) -> bool:
+async def check_embedding_endpoint(
+    client: httpx.AsyncClient,
+    config: EbookSearchConfig,
+    *,
+    timeout_seconds: float = 5.0,
+) -> bool:
     """Return whether the configured embedding endpoint answers a model listing."""
     try:
-        response = httpx.get(
+        response = await client.get(
             f"{config.embedding_base_url.rstrip('/')}/models",
             headers=auth_headers(config.embedding_api_key),
             timeout=timeout_seconds,
@@ -59,10 +80,15 @@ def check_embedding_endpoint(config: EbookSearchConfig, *, timeout_seconds: floa
     return True
 
 
-def check_chat_endpoint(config: EbookSearchConfig, *, timeout_seconds: float = 5.0) -> bool:
+async def check_chat_endpoint(
+    client: httpx.AsyncClient,
+    config: EbookSearchConfig,
+    *,
+    timeout_seconds: float = 5.0,
+) -> bool:
     """Return whether the configured chat (answering) endpoint answers a model listing."""
     try:
-        response = httpx.get(
+        response = await client.get(
             f"{config.vllm_base_url.rstrip('/')}/models",
             headers=auth_headers(config.vllm_api_key),
             timeout=timeout_seconds,
@@ -98,18 +124,29 @@ def embedding_vectors_from_response(body: object) -> list[list[float]]:
     return vectors
 
 
-def request_rerank(
+async def request_rerank(
+    client: httpx.AsyncClient,
     query: str,
     documents: Sequence[str],
     config: RerankConfig,
 ) -> object | None:
-    """Request rerank scores from the configured vLLM endpoint."""
+    """Request rerank scores from the configured vLLM endpoint.
+
+    Args:
+        client (httpx.AsyncClient): Shared async client for LLM calls.
+        query (str): Query the documents are scored against.
+        documents (Sequence[str]): Candidate documents to score.
+        config (RerankConfig): Rerank endpoint settings.
+
+    Returns:
+        object | None: The decoded response body, or ``None`` when it is not valid JSON.
+    """
     payload = {
         "model": config.model,
         "query": query,
         "documents": list(documents),
     }
-    response = httpx.post(
+    response = await client.post(
         f"{config.base_url.rstrip('/')}/rerank",
         json=payload,
         timeout=config.timeout_seconds,
@@ -122,13 +159,26 @@ def request_rerank(
         return None
 
 
-def request_chat_completion(
+async def request_chat_completion(
+    client: httpx.AsyncClient,
     config: EbookSearchConfig,
     messages: Sequence[dict[str, str]],
 ) -> str:
-    """Request a chat completion from the configured OpenAI-compatible endpoint."""
+    """Request a chat completion over a shared async client.
+
+    Args:
+        client (httpx.AsyncClient): Shared async client whose connection pool bounds concurrency.
+        config (EbookSearchConfig): Runtime settings supplying the endpoint, model, and auth.
+        messages (Sequence[dict[str, str]]): OpenAI-style chat messages.
+
+    Returns:
+        str: The assistant message text.
+
+    Raises:
+        RuntimeError: If the request fails or the response cannot be parsed.
+    """
     try:
-        response = httpx.post(
+        response = await client.post(
             f"{config.vllm_base_url.rstrip('/')}/chat/completions",
             headers=auth_headers(config.vllm_api_key),
             json={
diff --git a/python/ebook_search/protected_phrases/extraction.py b/python/ebook_search/protected_phrases/extraction.py
index 3af80a5..1370e5b 100644
--- a/python/ebook_search/protected_phrases/extraction.py
+++ b/python/ebook_search/protected_phrases/extraction.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import logging
 import re
-from collections import defaultdict
+from collections import Counter, defaultdict
 from functools import lru_cache
 from time import perf_counter
 from typing import TYPE_CHECKING, Protocol
@@ -15,6 +15,7 @@ from python.ebook_search.protected_phrases.config import (
     get_bad_ends,
     get_bad_starts,
     get_ignored_phrases,
+    get_junk_tokens,
     get_most_common_words,
 )
 from python.ebook_search.protected_phrases.models import PhraseCandidate
@@ -28,16 +29,10 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-BAD_START_SCORE_PENALTY = 3.0
-BAD_END_SCORE_PENALTY = 3.0
-SOURCE_FIELDS = (
-    "source_raw_ngram",
-    "source_yake",
-    "source_spacy_ner",
-    "source_spacy_noun_chunk",
-    "source_capitalized",
-    "source_metadata",
-)
+BAD_START_SCORE_PENALTY = 10.0
+BAD_END_SCORE_PENALTY = 10.0
+MULTI_SOURCE_SCORE_BONUS = 2.0
+MULTI_SOURCE_MIN_SOURCES = 2
 CAPITALIZED_PHRASE_RE = re.compile(r"\b(?:[A-Z][a-zA-Z']+)(?:\s+(?:of|the|and|in|on|for|[A-Z][a-zA-Z']+)){0,6}")
 
 
@@ -91,21 +86,6 @@ class YakeExtractorFactory(Protocol):
         """
 
 
-def strip_leading_articles(phrase_norm: str) -> str:
-    """Remove one leading English article from a normalized phrase.
-
-    Args:
-        phrase_norm (str): Normalized phrase text to strip.
-
-    Returns:
-        str: The phrase with a single leading ``the``, ``a``, or ``an`` removed.
-    """
-    tokens_ = phrase_norm.split()
-    if tokens_ and tokens_[0] in {"the", "a", "an"}:
-        tokens_ = tokens_[1:]
-    return " ".join(tokens_)
-
-
 def normalize_candidate_phrase(
     phrase_text: str,
     config: EbookSearchConfig,
@@ -146,35 +126,71 @@ def normalize_candidate_phrase(
     return display_text or phrase_norm, phrase_norm, len(selected_tokens)
 
 
-def extract_raw_ngrams(text: str, config: EbookSearchConfig) -> dict[str, PhraseCandidate]:
-    """Extract raw normalized n-grams as high-recall candidates.
+def count_raw_ngrams(tokens: Sequence[str], config: EbookSearchConfig) -> Counter[str]:
+    """Count every n-gram window in one normalized token block.
+
+    ``tokens`` are already normalized (see :func:`tokenize`), so each window's normalized form
+    is the joined tokens directly. Counting into a plain :class:`Counter` rather than
+    :class:`PhraseCandidate` objects keeps this hot loop cheap; callers filter ignored phrases
+    and materialize candidates per unique phrase afterwards, which is far fewer operations than
+    doing either per window.
 
     Args:
-        text (str): Book text to slide n-gram windows over.
+        tokens (Sequence[str]): Normalized tokens for one text block.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
 
     Returns:
-        dict[str, PhraseCandidate]: Candidates keyed by normalized phrase, with raw counts.
+        Counter[str]: Raw occurrence counts keyed by normalized phrase.
     """
-    tokens_ = tokenize(text)
-    out: dict[str, PhraseCandidate] = {}
-    for ngram_size in range(config.phrase_min_tokens, config.phrase_max_tokens + 1):
-        for start in range(len(tokens_) - ngram_size + 1):
-            normalized = normalize_candidate_phrase(" ".join(tokens_[start : start + ngram_size]), config)
-            if normalized is None:
-                continue
-            phrase_text, phrase_norm, token_count = normalized
-            item = out.setdefault(
-                phrase_norm,
-                PhraseCandidate(
-                    phrase_text=phrase_text,
-                    phrase_norm=phrase_norm,
-                    token_count=token_count,
-                    source_raw_ngram=True,
-                ),
-            )
-            item.raw_count += 1
-    return out
+    return Counter(
+        " ".join(tokens[start : start + ngram_size])
+        for ngram_size in range(config.phrase_min_tokens, config.phrase_max_tokens + 1)
+        for start in range(len(tokens) - ngram_size + 1)
+    )
+
+
+def extract_raw_ngrams_by_chapter(
+    chapters: Sequence[str],
+    config: EbookSearchConfig,
+) -> dict[str, PhraseCandidate]:
+    """Extract raw n-grams across chapters, tracking both raw counts and chapter spread.
+
+    Counting each chapter separately makes chapter spread fall out of dict membership: a phrase's
+    ``chapter_count`` is simply how many per-chapter count maps contain it, so no per-window seen
+    tracking is needed. This also lets the enrichment step skip re-sliding the same n-gram sizes.
+
+    Phrases below the minimum raw count are dropped here rather than materialized: most unique
+    n-grams occur once, and :func:`filter_storable_candidates` would discard them as too rare
+    anyway, so building ``PhraseCandidate`` objects for them is wasted work.
+
+    Args:
+        chapters (Sequence[str]): Chapter-like text blocks to slide n-gram windows over.
+        config (EbookSearchConfig): Runtime phrase-tuning settings.
+
+    Returns:
+        dict[str, PhraseCandidate]: Candidates meeting the minimum raw count, keyed by normalized
+        phrase, with raw and chapter counts.
+    """
+    chapter_count_maps = [count_raw_ngrams(tokenize(chapter), config) for chapter in chapters]
+    total_counts: Counter[str] = Counter()
+    chapter_spread: Counter[str] = Counter()
+    for chapter_counts in chapter_count_maps:
+        total_counts.update(chapter_counts)
+        chapter_spread.update(chapter_counts.keys())
+    min_raw_count = minimum_candidate_raw_count(config)
+    ignored = get_ignored_phrases()
+    return {
+        phrase_norm: PhraseCandidate(
+            phrase_text=phrase_norm,
+            phrase_norm=phrase_norm,
+            token_count=phrase_norm.count(" ") + 1,
+            source_raw_ngram=True,
+            raw_count=raw_count,
+            chapter_count=chapter_spread[phrase_norm],
+        )
+        for phrase_norm, raw_count in total_counts.items()
+        if raw_count >= min_raw_count and phrase_norm not in ignored
+    }
 
 
 @lru_cache(maxsize=2)
@@ -381,6 +397,7 @@ def merge_candidate(existing: PhraseCandidate, item: PhraseCandidate) -> None:
     existing.source_capitalized = existing.source_capitalized or item.source_capitalized
     existing.source_metadata = existing.source_metadata or item.source_metadata
     existing.raw_count += item.raw_count
+    existing.chapter_count = max(existing.chapter_count, item.chapter_count)
     if item.yake_score is not None:
         existing.yake_score = item.yake_score
     if item.spacy_label:
@@ -390,12 +407,19 @@ def merge_candidate(existing: PhraseCandidate, item: PhraseCandidate) -> None:
 def enrich_with_frequency_and_chapter_counts(
     candidates: Mapping[str, PhraseCandidate],
     chapters: Sequence[str],
+    *,
+    counted_sizes: Iterable[int] = (),
 ) -> dict[str, PhraseCandidate]:
     """Add raw occurrence and chapter-spread counts to candidates.
 
+    Candidates whose ``token_count`` is in ``counted_sizes`` are left untouched: those counts
+    were already computed while sliding the chapters in :func:`extract_raw_ngrams_by_chapter`,
+    so re-sliding those n-gram sizes here would just duplicate that work.
+
     Args:
         candidates (Mapping[str, PhraseCandidate]): Candidates to enrich, keyed by normalized phrase.
         chapters (Sequence[str]): Chapter-like text blocks used to count occurrences and spread.
+        counted_sizes (Iterable[int]): Token counts whose counts are already populated and should be skipped.
 
     Returns:
         dict[str, PhraseCandidate]: Candidates with updated ``raw_count`` and ``chapter_count`` values.
@@ -403,10 +427,40 @@ def enrich_with_frequency_and_chapter_counts(
     if not candidates:
         return {}
 
+    already_counted = set(counted_sizes)
     candidate_sets_by_size: dict[int, set[str]] = defaultdict(set)
     for phrase_norm, candidate in candidates.items():
+        if candidate.token_count in already_counted:
+            continue
         candidate_sets_by_size[candidate.token_count].add(phrase_norm)
 
+    enriched = dict(candidates)
+    if not candidate_sets_by_size:
+        return enriched
+
+    total_counts, chapter_counts = count_candidate_occurrences(candidate_sets_by_size, chapters)
+    for phrase_norm, candidate in enriched.items():
+        if candidate.token_count in already_counted:
+            continue
+        candidate.raw_count = max(candidate.raw_count, total_counts[phrase_norm])
+        candidate.chapter_count = chapter_counts[phrase_norm]
+    return enriched
+
+
+def count_candidate_occurrences(
+    candidate_sets_by_size: Mapping[int, set[str]],
+    chapters: Sequence[str],
+) -> tuple[dict[str, int], dict[str, int]]:
+    """Count total occurrences and chapter spread for candidate phrases across chapters.
+
+    Args:
+        candidate_sets_by_size (Mapping[int, set[str]]): Candidate normalized phrases grouped by token count.
+        chapters (Sequence[str]): Chapter-like text blocks to slide n-gram windows over.
+
+    Returns:
+        tuple[dict[str, int], dict[str, int]]: Total occurrence counts and chapter-spread counts,
+        each keyed by normalized phrase.
+    """
     total_counts: defaultdict[str, int] = defaultdict(int)
     chapter_counts: defaultdict[str, int] = defaultdict(int)
     for chapter in chapters:
@@ -421,18 +475,13 @@ def enrich_with_frequency_and_chapter_counts(
                 seen_in_chapter.add(phrase_norm)
         for phrase_norm in seen_in_chapter:
             chapter_counts[phrase_norm] += 1
-
-    enriched = dict(candidates)
-    for phrase_norm, candidate in enriched.items():
-        candidate.raw_count = max(candidate.raw_count, total_counts[phrase_norm])
-        candidate.chapter_count = chapter_counts[phrase_norm]
-    return enriched
+    return total_counts, chapter_counts
 
 
 def filter_storable_candidates(
     candidates: Mapping[str, PhraseCandidate],
     config: EbookSearchConfig,
-) -> tuple[dict[str, PhraseCandidate], int, int, int]:
+) -> tuple[dict[str, PhraseCandidate], int, int, int, int]:
     """Remove candidates that should not be persisted.
 
     Args:
@@ -440,14 +489,15 @@ def filter_storable_candidates(
         config (EbookSearchConfig): Runtime phrase-tuning settings.
 
     Returns:
-        tuple[dict[str, PhraseCandidate], int, int, int]: The storable candidates followed by the counts
-        dropped for being too short, too rare, and too common.
+        tuple[dict[str, PhraseCandidate], int, int, int, int]: The storable candidates followed by the
+        counts dropped for being too short, too rare, too common, and junk.
     """
     min_raw_count = minimum_candidate_raw_count(config)
     filtered: dict[str, PhraseCandidate] = {}
     too_short = 0
     too_rare = 0
     too_common = 0
+    junk = 0
     for phrase_norm, candidate in candidates.items():
         if candidate.token_count < config.phrase_min_tokens:
             too_short += 1
@@ -455,11 +505,15 @@ def filter_storable_candidates(
         if candidate.raw_count < min_raw_count:
             too_rare += 1
             continue
-        if is_most_common_word_phrase(phrase_norm):
+        phrase_tokens = phrase_norm.split()
+        if is_most_common_word_phrase(phrase_tokens):
             too_common += 1
             continue
+        if is_junk_phrase(phrase_tokens):
+            junk += 1
+            continue
         filtered[phrase_norm] = candidate
-    return filtered, too_short, too_rare, too_common
+    return filtered, too_short, too_rare, too_common, junk
 
 
 def minimum_candidate_raw_count(config: EbookSearchConfig) -> int:
@@ -474,18 +528,41 @@ def minimum_candidate_raw_count(config: EbookSearchConfig) -> int:
     return max(config.phrase_raw_ngram_min_count, 1)
 
 
-def is_most_common_word_phrase(phrase_norm: str) -> bool:
+def is_most_common_word_phrase(phrase_tokens: list[str]) -> bool:
     """Return whether every token in a normalized phrase is a common word.
 
     Args:
-        phrase_norm (str): Normalized phrase text to inspect.
+        phrase_tokens (list[str]): Normalized phrase tokens to inspect.
 
     Returns:
         bool: True when the phrase is non-empty and every token is a common word.
     """
-    tokens_ = phrase_norm.split()
     common_words = get_most_common_words()
-    return bool(tokens_) and all(token in common_words for token in tokens_)
+    return bool(phrase_tokens) and all(token in common_words for token in phrase_tokens)
+
+
+def is_junk_phrase(phrase_tokens: list[str]) -> bool:
+    """Return whether a normalized phrase is lexical junk not worth LLM judging.
+
+    Judged data shows phrases containing a dialogue/action verb or a pronoun contraction are
+    never kept, and phrases whose tokens are mostly common words almost never are. Possessives
+    of proper nouns (``chapman's death``) pass because matching is by exact token, and
+    exactly-half-common bigrams (``data feed``) pass because the common-word rule is strict.
+
+    Args:
+        phrase_tokens (list[str]): Normalized phrase tokens to inspect.
+
+    Returns:
+        bool: True when the phrase contains a junk token or is majority common words.
+    """
+    if not phrase_tokens:
+        return False
+    junk_tokens = get_junk_tokens()
+    if any(token in junk_tokens for token in phrase_tokens):
+        return True
+    common_words = get_most_common_words()
+    half_phrase_len = len(phrase_tokens) // 2
+    return sum(token in common_words for token in phrase_tokens) > half_phrase_len
 
 
 def score_candidate(candidate: PhraseCandidate, config: EbookSearchConfig) -> float:
@@ -499,6 +576,8 @@ def score_candidate(candidate: PhraseCandidate, config: EbookSearchConfig) -> fl
         float: Combined score from sources, frequency, and length, less any penalties.
     """
     score = source_score(candidate) + frequency_score(candidate, config) + token_count_score(candidate, config)
+    if non_raw_source_count(candidate) >= MULTI_SOURCE_MIN_SOURCES:
+        score += MULTI_SOURCE_SCORE_BONUS
     if candidate.phrase_norm in get_ignored_phrases():
         score -= 100.0
     if has_bad_start(candidate.phrase_norm):
@@ -508,6 +587,26 @@ def score_candidate(candidate: PhraseCandidate, config: EbookSearchConfig) -> fl
     return score
 
 
+def non_raw_source_count(candidate: PhraseCandidate) -> int:
+    """Count the non-raw-ngram extraction sources that produced a candidate.
+
+    Args:
+        candidate (PhraseCandidate): Candidate whose enabled sources are counted.
+
+    Returns:
+        int: Number of enabled sources other than the raw n-gram slide.
+    """
+    return sum(
+        (
+            candidate.source_yake,
+            candidate.source_spacy_ner,
+            candidate.source_spacy_noun_chunk,
+            candidate.source_capitalized,
+            candidate.source_metadata,
+        )
+    )
+
+
 def has_bad_start(phrase_norm: str) -> bool:
     """Return whether a normalized phrase starts with a bad starting token.
 
@@ -517,8 +616,8 @@ def has_bad_start(phrase_norm: str) -> bool:
     Returns:
         bool: True when the first token is a known bad starting token.
     """
-    tokens_ = phrase_norm.split()
-    return bool(tokens_ and tokens_[0] in get_bad_starts())
+    phrase_tokens = phrase_norm.split()
+    return bool(phrase_tokens and phrase_tokens[0] in get_bad_starts())
 
 
 def has_bad_end(phrase_norm: str) -> bool:
@@ -530,8 +629,8 @@ def has_bad_end(phrase_norm: str) -> bool:
     Returns:
         bool: True when the last token is a known bad ending token.
     """
-    tokens_ = phrase_norm.split()
-    return bool(tokens_ and tokens_[-1] in get_bad_ends())
+    phrase_tokens = phrase_norm.split()
+    return bool(phrase_tokens and phrase_tokens[-1] in get_bad_ends())
 
 
 def source_score(candidate: PhraseCandidate) -> float:
@@ -550,6 +649,7 @@ def source_score(candidate: PhraseCandidate) -> float:
             (candidate.source_spacy_ner, 2.5),
             (candidate.source_spacy_noun_chunk, 1.5),
             (candidate.source_capitalized, 2.0),
+            (candidate.source_metadata, 2.0),
             (candidate.source_raw_ngram, 0.5),
         )
         if enabled
@@ -569,10 +669,10 @@ def frequency_score(candidate: PhraseCandidate, config: EbookSearchConfig) -> fl
     return sum(
         weight
         for count, threshold, weight in (
-            (candidate.raw_count, config.phrase_raw_count_score_threshold, 1.0),
-            (candidate.raw_count, config.phrase_raw_count_high_score_threshold, 1.0),
-            (candidate.chapter_count, config.phrase_chapter_count_score_threshold, 1.0),
-            (candidate.chapter_count, config.phrase_chapter_count_high_score_threshold, 1.0),
+            (candidate.raw_count, config.phrase_raw_count_score_threshold, 0.5),
+            (candidate.raw_count, config.phrase_raw_count_high_score_threshold, 0.5),
+            (candidate.chapter_count, config.phrase_chapter_count_score_threshold, 0.5),
+            (candidate.chapter_count, config.phrase_chapter_count_high_score_threshold, 0.5),
         )
         if count >= threshold
     )
@@ -679,7 +779,7 @@ def extract_phrase_candidates_for_book(
         config.protected_phrase_max_candidates_per_book,
     )
     raw_started_at = perf_counter()
-    raw = extract_raw_ngrams(book_text, config)
+    raw = extract_raw_ngrams_by_chapter(chapters, config)
     logger.info(
         "ebook_phrase_candidate_extract_raw_complete candidates=%s duration_ms=%.1f",
         len(raw),
@@ -713,11 +813,16 @@ def extract_phrase_candidates_for_book(
 
     candidates = merge_candidate_sources(raw, yake_candidates, spacy_candidates, capitalized, metadata_candidates)
     enriched_started_at = perf_counter()
-    candidates = enrich_with_frequency_and_chapter_counts(candidates, chapters)
-    pre_filter_count = len(candidates)
-    candidates, filtered_too_short, filtered_too_rare, filtered_too_common = filter_storable_candidates(
+    # Raw n-gram sizes were already counted per chapter above, so only enrich the remaining
+    # (entity-length) sizes here instead of re-sliding every size over the whole book.
+    candidates = enrich_with_frequency_and_chapter_counts(
         candidates,
-        config,
+        chapters,
+        counted_sizes=range(config.phrase_min_tokens, config.phrase_max_tokens + 1),
+    )
+    pre_filter_count = len(candidates)
+    candidates, filtered_too_short, filtered_too_rare, filtered_too_common, filtered_junk = filter_storable_candidates(
+        candidates, config
     )
     for candidate in candidates.values():
         candidate.candidate_score = score_candidate(candidate, config)
@@ -727,8 +832,8 @@ def extract_phrase_candidates_for_book(
     ]
     logger.info(
         "ebook_phrase_candidate_extract_complete raw=%s yake=%s spacy=%s capitalized=%s metadata=%s "
-        "merged=%s filtered_too_short=%s filtered_too_rare=%s filtered_too_common=%s min_uses=%s "
-        "storable=%s limited=%s enrich_score_ms=%.1f duration_ms=%.1f",
+        "merged=%s filtered_too_short=%s filtered_too_rare=%s filtered_too_common=%s filtered_junk=%s "
+        "min_uses=%s storable=%s limited=%s enrich_score_ms=%.1f duration_ms=%.1f",
         len(raw),
         len(yake_candidates),
         len(spacy_candidates),
@@ -738,6 +843,7 @@ def extract_phrase_candidates_for_book(
         filtered_too_short,
         filtered_too_rare,
         filtered_too_common,
+        filtered_junk,
         minimum_candidate_raw_count(config),
         len(candidates),
         len(limited),
diff --git a/python/ebook_search/protected_phrases/generate_ngrams.py b/python/ebook_search/protected_phrases/generate_ngrams.py
index c3a6499..165d9b5 100644
--- a/python/ebook_search/protected_phrases/generate_ngrams.py
+++ b/python/ebook_search/protected_phrases/generate_ngrams.py
@@ -2,7 +2,9 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
+from collections import deque
 from time import perf_counter
 from typing import TYPE_CHECKING
 
@@ -14,44 +16,55 @@ from python.ebook_search.protected_phrases.models import (
     PhraseCandidateGenerationResult,
     PhraseRecalculationResult,
 )
+from python.ebook_search.protected_phrases.pool import extract_phrase_candidates_in_pool, get_extraction_pool
 from python.ebook_search.protected_phrases.store import (
+    bulk_upsert_unjudged_candidates,
     delete_phrase_data_for_book,
     load_book_chapter_texts,
     metadata_for_source,
+    new_candidate_row,
     prune_unstorable_unjudged_candidate_phrases,
-    save_candidate_to_db,
 )
-from python.orm.richie import EbookSource
+from python.orm.richie import EbookCandidatePhrase, EbookSource
 
 if TYPE_CHECKING:
     from collections.abc import Mapping, Sequence
+    from concurrent.futures import Future
 
-    from sqlalchemy.orm import Session
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.protected_phrases.extraction import SpacyLanguage
-    from python.orm.richie import EbookCandidatePhrase
+    from python.ebook_search.protected_phrases.models import PhraseCandidate
 
 logger = logging.getLogger(__name__)
 
 
-def generate_candidate_phrases_for_books(
-    session: Session,
+async def generate_candidate_phrases_for_books(
+    session: AsyncSession,
     config: EbookSearchConfig,
     *,
-    nlp: SpacyLanguage | None = None,
+    only_missing: bool = False,
 ) -> PhraseCandidateGenerationResult:
     """Create or refresh candidate phrases for indexed books without calling the LLM judge.
 
+    Extraction always runs concurrently in the shared process pool so a full backfill uses
+    multiple cores.
+
     Args:
         session (Session): Active database session.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
-        nlp (SpacyLanguage | None): Optional spaCy pipeline for entity and noun-chunk sources.
+        only_missing (bool): When True, only generate for books that have no candidate phrases
+            yet instead of refreshing every book.
 
     Returns:
         PhraseCandidateGenerationResult: Per-corpus counts of books seen, built, and candidates stored.
     """
-    sources = session.scalars(select(EbookSource).order_by(EbookSource.id)).all()
+    source_query = select(EbookSource).order_by(EbookSource.id)
+    if only_missing:
+        has_candidates = select(EbookCandidatePhrase.id).where(EbookCandidatePhrase.book_id == EbookSource.id)
+        source_query = source_query.where(~has_candidates.exists())
+    sources = (await session.scalars(source_query)).all()
     books_seen = len(sources)
     logger.info(
         "ebook_candidate_phrase_generation_start books_seen=%s min_tokens=%s max_tokens=%s max_candidates_per_book=%s",
@@ -61,7 +74,7 @@ def generate_candidate_phrases_for_books(
         config.protected_phrase_max_candidates_per_book,
     )
 
-    outcomes = [generate_candidates_for_source(session, source, config, nlp=nlp) for source in sources]
+    outcomes = await generate_candidates_for_sources_pooled(session, sources, config)
 
     result = PhraseCandidateGenerationResult(
         books_seen=books_seen,
@@ -77,76 +90,99 @@ def generate_candidate_phrases_for_books(
     return result
 
 
-def generate_candidates_for_source(
-    session: Session,
-    source: EbookSource,
+async def generate_candidates_for_sources_pooled(
+    session: AsyncSession,
+    sources: Sequence[EbookSource],
     config: EbookSearchConfig,
-    *,
-    nlp: SpacyLanguage | None = None,
-) -> BookCandidateResult:
-    """Generate and store candidate phrases for one book, managing its own transaction.
+) -> list[BookCandidateResult]:
+    """Generate candidate phrases for many books, extracting them concurrently in worker processes.
 
-    Commits on success; rolls back and re-raises on error so callers stop the backfill.
+    Chapter loading and row persistence stay on the caller's session (serial), while the CPU-bound
+    extraction runs in the shared process pool. A bounded window of in-flight books overlaps
+    extraction across cores without loading every book's candidates into memory at once.
 
     Args:
         session (Session): Active database session.
-        source (EbookSource): Indexed book to generate candidates for.
+        sources (Sequence[EbookSource]): Indexed books to generate candidates for.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
-        nlp (SpacyLanguage | None): Optional spaCy pipeline for entity and noun-chunk sources.
 
     Returns:
-        BookCandidateResult: Candidate count and whether the book was committed.
+        list[BookCandidateResult]: One result per book.
+    """
+    pool = get_extraction_pool(config.protected_phrase_extraction_workers)
+    max_in_flight = max(1, config.protected_phrase_extraction_workers) * 2
+    pending: deque[tuple[EbookSource, Future[list[PhraseCandidate]]]] = deque()
+    outcomes: list[BookCandidateResult] = []
+
+    async def drain_one() -> None:
+        source, future = pending.popleft()
+        extracted = await asyncio.wrap_future(future)
+        outcomes.append(await store_source_candidates(session, source, extracted, config))
+
+    try:
+        for source in sources:
+            chapters = await load_book_chapter_texts(session, source.id)
+            if not chapters:
+                logger.warning("ebook_candidate_phrase_generation_book_empty source_id=%s", source.id)
+                outcomes.append(BookCandidateResult())
+                continue
+            future = pool.submit(
+                extract_phrase_candidates_for_book,
+                "\n\n".join(chapters),
+                chapters,
+                config,
+                metadata=metadata_for_source(source),
+            )
+            pending.append((source, future))
+            if len(pending) >= max_in_flight:
+                await drain_one()
+        while pending:
+            await drain_one()
+    except Exception:
+        for _, future in pending:
+            future.cancel()
+        await session.rollback()
+        logger.exception("ebook_candidate_phrase_generation_pooled_failed")
+        raise
+    return outcomes
+
+
+async def store_source_candidates(
+    session: AsyncSession,
+    source: EbookSource,
+    limited_candidates: list[PhraseCandidate],
+    config: EbookSearchConfig,
+) -> BookCandidateResult:
+    """Persist and commit one book's already-extracted candidates.
+
+    Args:
+        session (AsyncSession): Active database session.
+        source (EbookSource): Book the candidates belong to.
+        limited_candidates (list[PhraseCandidate]): Scored candidates to persist.
+        config (EbookSearchConfig): Runtime phrase-tuning settings.
+
+    Returns:
+        BookCandidateResult: Candidate count and that the book was committed.
     """
     book_started_at = perf_counter()
-    logger.info(
-        "ebook_candidate_phrase_generation_book_start source_id=%s title=%r",
-        source.id,
-        source.title,
-    )
-    try:
-        chapters = load_book_chapter_texts(session, source.id)
-        if not chapters:
-            logger.warning("ebook_candidate_phrase_generation_book_empty source_id=%s", source.id)
-            return BookCandidateResult()
-        book_text = "\n\n".join(chapters)
-        logger.info(
-            "ebook_candidate_phrase_generation_book_loaded source_id=%s chapters=%s chars=%s",
-            source.id,
-            len(chapters),
-            len(book_text),
-        )
-
-        candidates = generate_candidate_phrases_for_book(
-            session,
-            source.id,
-            series_id=None,
-            book_text=book_text,
-            chapters=chapters,
-            config=config,
-            nlp=nlp,
-            metadata=metadata_for_source(source),
-        )
-        session.commit()
-    except Exception:
-        session.rollback()
-        logger.exception("ebook_candidate_phrase_generation_book_failed source_id=%s", source.id)
-        raise
-
+    saved_count = await store_candidate_phrases_for_book(session, source.id, None, limited_candidates, config)
+    await session.commit()
     logger.info(
         "ebook_candidate_phrase_generation_book_committed source_id=%s candidates=%s duration_ms=%.1f",
         source.id,
-        len(candidates),
+        saved_count,
         (perf_counter() - book_started_at) * 1000,
     )
-    return BookCandidateResult(candidates=len(candidates), built=True)
+    return BookCandidateResult(candidates=saved_count, built=True)
 
 
-def recalculate_candidate_phrases_for_book(
-    session: Session,
+async def recalculate_candidate_phrases_for_book(
+    session: AsyncSession,
     source: EbookSource,
     config: EbookSearchConfig,
     *,
     nlp: SpacyLanguage | None = None,
+    use_process_pool: bool = False,
 ) -> PhraseRecalculationResult:
     """Remove all book phrase data, regenerate candidates, and commit the completed book.
 
@@ -155,6 +191,9 @@ def recalculate_candidate_phrases_for_book(
         source (EbookSource): Indexed book to recalculate.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
         nlp (SpacyLanguage | None): Optional spaCy pipeline for entity and noun-chunk sources.
+        use_process_pool (bool): Run the CPU-bound extraction in a worker process so concurrent
+            recalculations do not serialize behind the GIL. Defaults to in-process for callers
+            (tests, backfills) that do not need it.
 
     Returns:
         PhraseRecalculationResult: Deleted-row counts and the number of candidates regenerated.
@@ -166,11 +205,11 @@ def recalculate_candidate_phrases_for_book(
         source.title,
     )
     try:
-        deleted = delete_phrase_data_for_book(session, source.id)
-        chapters = load_book_chapter_texts(session, source.id)
+        deleted = await delete_phrase_data_for_book(session, source.id)
+        chapters = await load_book_chapter_texts(session, source.id)
         if not chapters:
             logger.warning("ebook_candidate_phrase_recalculation_book_empty source_id=%s", source.id)
-            session.commit()
+            await session.commit()
             return PhraseRecalculationResult(
                 book_id=source.id,
                 deleted_candidates=deleted.deleted_candidates,
@@ -180,19 +219,20 @@ def recalculate_candidate_phrases_for_book(
                 candidate_phrases=0,
             )
 
-        candidates = generate_candidate_phrases_for_book(
+        candidate_count = await generate_candidate_phrases_for_book(
             session,
             source.id,
             series_id=None,
-            book_text="\n\n".join(chapters),
             chapters=chapters,
             config=config,
             nlp=nlp,
             metadata=metadata_for_source(source),
+            replace_all=True,
+            use_process_pool=use_process_pool,
         )
-        session.commit()
+        await session.commit()
     except Exception:
-        session.rollback()
+        await session.rollback()
         logger.exception("ebook_candidate_phrase_recalculation_failed source_id=%s", source.id)
         raise
 
@@ -202,7 +242,7 @@ def recalculate_candidate_phrases_for_book(
         deleted_protected_phrases=deleted.deleted_protected_phrases,
         deleted_aliases=deleted.deleted_aliases,
         deleted_mentions=deleted.deleted_mentions,
-        candidate_phrases=len(candidates),
+        candidate_phrases=candidate_count,
     )
     logger.info(
         "ebook_candidate_phrase_recalculation_complete source_id=%s deleted_candidates=%s "
@@ -218,57 +258,113 @@ def recalculate_candidate_phrases_for_book(
     return result
 
 
-def generate_candidate_phrases_for_book(
-    session: Session,
+async def generate_candidate_phrases_for_book(
+    session: AsyncSession,
     book_id: int,
     series_id: int | None,
-    book_text: str,
     chapters: Sequence[str],
     config: EbookSearchConfig,
     *,
     nlp: SpacyLanguage | None = None,
     metadata: Mapping[str, object] | None = None,
-) -> list[EbookCandidatePhrase]:
+    replace_all: bool = False,
+    use_process_pool: bool = False,
+) -> int:
     """Extract and store candidate phrases for one book without LLM judging.
 
     Args:
         session (Session): Active database session.
         book_id (int): Book the candidates belong to.
         series_id (int | None): Series scope for the stored candidates.
-        book_text (str): Full book text used for extraction.
-        chapters (Sequence[str]): Chapter-like text blocks used for frequency counts.
+        chapters (Sequence[str]): Chapter-like text blocks used for extraction and frequency counts.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
         nlp (SpacyLanguage | None): Optional spaCy pipeline for entity and noun-chunk sources.
         metadata (Mapping[str, object] | None): Optional book metadata used as a candidate source.
+        replace_all (bool): When the caller has already cleared this book's candidates (e.g. a
+            recalculation), skip the per-candidate existence lookup and bulk-insert new rows.
+        use_process_pool (bool): Run the CPU-bound extraction in a worker process to avoid
+            serializing concurrent requests behind the GIL. Ignored when ``nlp`` is set, since
+            the spaCy pipeline cannot be sent to a worker process.
 
     Returns:
-        list[EbookCandidatePhrase]: The stored candidate phrase rows.
+        int: Number of candidate phrase rows stored.
     """
     started_at = perf_counter()
-    limited_candidates = extract_phrase_candidates_for_book(
-        book_text,
-        chapters,
+    book_text = "\n\n".join(chapters)
+    if use_process_pool and nlp is None:
+        limited_candidates = await extract_phrase_candidates_in_pool(book_text, chapters, config, metadata=metadata)
+    else:
+        limited_candidates = extract_phrase_candidates_for_book(
+            book_text,
+            chapters,
+            config,
+            nlp=nlp,
+            metadata=metadata,
+        )
+    saved_count = await store_candidate_phrases_for_book(
+        session,
+        book_id,
+        series_id,
+        limited_candidates,
         config,
-        nlp=nlp,
-        metadata=metadata,
+        replace_all=replace_all,
     )
-    save_started_at = perf_counter()
-    pruned_count = prune_unstorable_unjudged_candidate_phrases(session, book_id, config)
     logger.info(
-        "ebook_candidate_phrase_save_start book_id=%s candidates=%s pruned_unstorable=%s",
+        "ebook_candidate_phrase_generation_book_duration book_id=%s candidates=%s duration_ms=%.1f",
         book_id,
-        len(limited_candidates),
-        pruned_count,
-    )
-    rows = [
-        save_candidate_to_db(session, book_id, series_id, candidate, judgment=None) for candidate in limited_candidates
-    ]
-    session.flush()
-    logger.info(
-        "ebook_candidate_phrase_generation_complete book_id=%s candidates=%s save_ms=%.1f duration_ms=%.1f",
-        book_id,
-        len(rows),
-        (perf_counter() - save_started_at) * 1000,
+        saved_count,
         (perf_counter() - started_at) * 1000,
     )
-    return rows
+    return saved_count
+
+
+async def store_candidate_phrases_for_book(
+    session: AsyncSession,
+    book_id: int,
+    series_id: int | None,
+    limited_candidates: list[PhraseCandidate],
+    config: EbookSearchConfig,
+    *,
+    replace_all: bool = False,
+) -> int:
+    """Persist already-extracted candidate phrase rows for one book without committing.
+
+    Args:
+        session (Session): Active database session.
+        book_id (int): Book the candidates belong to.
+        series_id (int | None): Series scope for the stored candidates.
+        limited_candidates (list[PhraseCandidate]): Scored candidates to persist.
+        config (EbookSearchConfig): Runtime phrase-tuning settings.
+        replace_all (bool): When the caller has already cleared this book's candidates, skip the
+            per-candidate existence lookup and bulk-insert new rows.
+
+    Returns:
+        int: Number of candidate phrase rows stored.
+    """
+    save_started_at = perf_counter()
+    if replace_all:
+        rows = [new_candidate_row(book_id, series_id, candidate) for candidate in limited_candidates]
+        session.add_all(rows)
+        await session.flush()
+        saved_count = len(rows)
+        logger.info(
+            "ebook_candidate_phrase_save_start book_id=%s candidates=%s mode=bulk_insert",
+            book_id,
+            len(limited_candidates),
+        )
+    else:
+        pruned_count = await prune_unstorable_unjudged_candidate_phrases(session, book_id, config)
+        logger.info(
+            "ebook_candidate_phrase_save_start book_id=%s candidates=%s pruned_unstorable=%s",
+            book_id,
+            len(limited_candidates),
+            pruned_count,
+        )
+        saved_count = await bulk_upsert_unjudged_candidates(session, book_id, series_id, limited_candidates)
+    logger.info(
+        "ebook_candidate_phrase_save_complete book_id=%s candidates=%s save_ms=%.1f",
+        book_id,
+        saved_count,
+        (perf_counter() - save_started_at) * 1000,
+    )
+    return saved_count
diff --git a/python/ebook_search/protected_phrases/judge_ngrams.py b/python/ebook_search/protected_phrases/judge_ngrams.py
index 1be6e17..56b6b70 100644
--- a/python/ebook_search/protected_phrases/judge_ngrams.py
+++ b/python/ebook_search/protected_phrases/judge_ngrams.py
@@ -2,20 +2,24 @@
 
 from __future__ import annotations
 
+import asyncio
 import json
 import logging
 import re
 from time import perf_counter
 from typing import TYPE_CHECKING
 
+import httpx
 from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
 
 from python.ebook_search.llm_interface import request_chat_completion
 from python.ebook_search.protected_phrases.extraction import (
     candidate_source_names,
     get_sample_contexts,
+    is_junk_phrase,
     is_most_common_word_phrase,
-    minimum_candidate_raw_count,
+    score_candidate,
 )
 from python.ebook_search.protected_phrases.matching import index_chunk_phrase_mentions_for_book
 from python.ebook_search.protected_phrases.models import BookJudgmentResult, LLMJudgment, PhraseJudgmentBackfillResult
@@ -32,47 +36,65 @@ from python.ebook_search.protected_phrases.text_normalization import normalize_t
 from python.orm.richie import EbookSource
 
 if TYPE_CHECKING:
-    from sqlalchemy.orm import Session
+    from collections.abc import Sequence
+
+    from sqlalchemy.ext.asyncio import AsyncEngine
 
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.protected_phrases.models import PhraseCandidate
-    from python.orm.richie import EbookCandidatePhrase, EbookProtectedPhrase
+    from python.orm.richie import EbookProtectedPhrase
 
 JSON_OBJECT_RE = re.compile(r"\{.*\}", re.DOTALL)
 
 
-
 logger = logging.getLogger(__name__)
 
 
-def judge_candidate_phrases_for_books(
-    session: Session,
+async def judge_candidate_phrases_for_books(
+    engine: AsyncEngine,
     config: EbookSearchConfig,
+    *,
+    source_ids: Sequence[int] | None = None,
 ) -> PhraseJudgmentBackfillResult:
-    """Judge stored candidate phrases and promote accepted phrases for indexed books.
+    """Judge candidate phrases for books, fanning LLM calls out across books and phrases.
+
+    Up to ``phrase_judge_book_workers`` books are judged at once, and within each book candidates
+    are judged in concurrent chunks of ``phrase_judge_phrase_workers``. Each book uses its own
+    short-lived sessions for reads and writes; no database connection is held while LLM calls are
+    in flight. For a pseudo-single-threaded run (solo testing, debugging), set both worker
+    settings to 1.
 
     Args:
-        session (Session): Active database session.
-        config (EbookSearchConfig): Runtime phrase-tuning settings.
+        engine (AsyncEngine): Engine used to open one session per book.
+        config (EbookSearchConfig): Runtime phrase-tuning settings and chat configuration.
+        source_ids (Sequence[int] | None): Books to judge; ``None`` judges every indexed book.
 
     Returns:
         PhraseJudgmentBackfillResult: Per-corpus counts of books judged, failures, candidates,
         protected phrases, and mentions.
     """
-    source_ids = session.scalars(select(EbookSource.id).order_by(EbookSource.id)).all()
+    if source_ids is None:
+        async with AsyncSession(engine) as session:
+            source_ids = list((await session.scalars(select(EbookSource.id).order_by(EbookSource.id))).all())
     books_seen = len(source_ids)
+    book_workers = max(1, config.phrase_judge_book_workers)
+    phrase_workers = max(1, config.phrase_judge_phrase_workers)
     logger.info(
-        "ebook_candidate_phrase_judgment_start books_seen=%s llm_candidates_per_book=%s "
-        "target_protected_per_book=%s confidence_threshold=%.2f min_tokens=%s min_uses=%s",
+        "ebook_candidate_phrase_judgment_start books_seen=%s book_workers=%s phrase_workers=%s "
+        "confidence_threshold=%.2f",
         books_seen,
-        config.protected_phrase_llm_candidates_per_book,
-        config.phrase_target_protected_per_book,
+        book_workers,
+        phrase_workers,
         config.protected_phrase_confidence_threshold,
-        config.phrase_min_tokens,
-        minimum_candidate_raw_count(config),
     )
 
-    outcomes = [judge_book_for_backfill(session, source_id, config) for source_id in source_ids]
+    book_semaphore = asyncio.Semaphore(book_workers)
+    max_connections = book_workers * phrase_workers
+    limits = httpx.Limits(max_connections=max_connections, max_keepalive_connections=max_connections)
+    async with httpx.AsyncClient(limits=limits) as client:
+        outcomes = await asyncio.gather(
+            *(judge_one_book_async(engine, source_id, config, client, book_semaphore) for source_id in source_ids)
+        )
 
     result = PhraseJudgmentBackfillResult(
         books_seen=books_seen,
@@ -95,235 +117,247 @@ def judge_candidate_phrases_for_books(
     return result
 
 
-def judge_book_for_backfill(
-    session: Session,
+async def judge_one_book_async(
+    engine: AsyncEngine,
     source_id: int,
     config: EbookSearchConfig,
+    client: httpx.AsyncClient,
+    book_semaphore: asyncio.Semaphore,
 ) -> BookJudgmentResult:
-    """Judge one book's candidates and return its outcome.
+    """Judge one book concurrently and persist the outcome, honoring the book-level limit.
 
     Args:
-        session (Session): Active database session.
+        engine (AsyncEngine): Engine used to open the book's read and write sessions.
         source_id (int): Book to judge candidates for.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
+        client (httpx.AsyncClient): Shared async client for LLM calls.
+        book_semaphore (asyncio.Semaphore): Caps how many books judge at once.
 
     Returns:
-        BookJudgmentResult: The book's judgment outcome, or an empty result when nothing was unjudged.
+        BookJudgmentResult: The book's judgment outcome.
     """
-    unjudged_count = count_unjudged_candidates(session, source_id, config)
-    if not unjudged_count:
-        logger.info(
-            "ebook_candidate_phrase_judgment_book_skip_no_unjudged source_id=%s",
-            source_id,
-        )
-        return BookJudgmentResult()
-    logger.info(
-        "ebook_candidate_phrase_judgment_book_start source_id=%s unjudged=%s",
-        source_id,
-        unjudged_count,
-    )
-    return run_book_judgment(session, source_id, unjudged_count, config)
+    async with book_semaphore:
+        try:
+            prepared = await prepare_book_judgment(engine, source_id, config)
+            if prepared is None:
+                return BookJudgmentResult()
+            work_items, target_remaining = prepared
+            judged = await judge_book_candidates_async(client, config, source_id, work_items, target_remaining)
+            if not judged:
+                return BookJudgmentResult()
+            return await persist_book_judgments(engine, source_id, config, judged)
+        except Exception:
+            logger.exception("ebook_candidate_phrase_judgment_book_failed source_id=%s", source_id)
+            return BookJudgmentResult(failed=True)
 
 
-def run_book_judgment(
-    session: Session,
+async def prepare_book_judgment(
+    engine: AsyncEngine,
     source_id: int,
-    unjudged_count: int,
     config: EbookSearchConfig,
-) -> BookJudgmentResult:
-    """Judge and index one book's candidates, managing its own transaction.
-
-    Commits on success and rolls back on error, returning a :class:`BookJudgmentResult`
-    that describes the outcome rather than raising it to the caller.
+) -> tuple[list[tuple[int, PhraseCandidate]], int | None] | None:
+    """Load one book's candidates to judge, with sample contexts, on a short-lived read session.
 
     Args:
-        session (Session): Active database session.
-        source_id (int): Book to judge candidates for.
-        unjudged_count (int): Storable unjudged candidates counted before judging, for logging.
+        engine (AsyncEngine): Engine used to open the read session.
+        source_id (int): Book to load candidates for.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
 
     Returns:
-        BookJudgmentResult: Judged, protected, and mention counts with commit and failure flags.
-    """
-    book_started_at = perf_counter()
-    try:
-        book_text = load_book_text(session, source_id)
-        if not book_text:
-            logger.warning("ebook_candidate_phrase_judgment_book_empty source_id=%s", source_id)
-            return BookJudgmentResult()
-
-        judged, protected = judge_candidate_phrases_for_book(
-            session,
-            source_id,
-            series_id=None,
-            normalized_book_text=normalize_text(book_text),
-            config=config,
-        )
-        if judged == 0:
-            logger.info(
-                "ebook_candidate_phrase_judgment_book_skip_no_judgments source_id=%s unjudged=%s",
-                source_id,
-                unjudged_count,
-            )
-            return BookJudgmentResult()
-
-        mentions = index_chunk_phrase_mentions_for_book(session, source_id, config) if protected else 0
-        session.commit()
-    except Exception:
-        session.rollback()
-        logger.exception("ebook_candidate_phrase_judgment_book_failed source_id=%s", source_id)
-        return BookJudgmentResult(failed=True)
-
-    logger.info(
-        "ebook_candidate_phrase_judgment_book_committed source_id=%s judged=%s protected=%s mentions=%s "
-        "duration_ms=%.1f",
-        source_id,
-        judged,
-        len(protected),
-        mentions,
-        (perf_counter() - book_started_at) * 1000,
-    )
-    return BookJudgmentResult(judged=judged, protected=len(protected), mentions=mentions, committed=True)
-
-
-def judge_candidate_phrases_for_book(
-    session: Session,
-    book_id: int,
-    series_id: int | None,
-    normalized_book_text: str,
-    config: EbookSearchConfig,
-) -> tuple[int, list[EbookProtectedPhrase]]:
-    """Judge unjudged candidate phrase rows for one book.
-
-    Args:
-        session (Session): Active database session.
-        book_id (int): Book whose candidates are judged.
-        series_id (int | None): Series scope for promoted protected phrases.
-        normalized_book_text (str): Whole book text, already normalized, for context lookups.
-        config (EbookSearchConfig): Runtime phrase-tuning settings.
-
-    Returns:
-        tuple[int, list[EbookProtectedPhrase]]: Number of candidates judged and the promoted phrases.
+        tuple[list[tuple[int, PhraseCandidate]], int | None] | None: Candidate rows paired with
+        in-memory candidates and the remaining protected-phrase target, or ``None`` when the book
+        has nothing to judge.
     """
     judgment_limit = config.protected_phrase_llm_candidates_per_book
     if judgment_limit <= 0:
-        logger.info("ebook_candidate_phrase_judgment_skipped_llm_limit_zero book_id=%s", book_id)
-        return 0, []
-
-    existing_protected = count_protected_phrases(session, book_id)
-    target_remaining: int | None = None
-    if config.phrase_target_protected_per_book > 0:
-        target_remaining = max(config.phrase_target_protected_per_book - existing_protected, 0)
-        if target_remaining == 0:
-            logger.info(
-                "ebook_candidate_phrase_judgment_skipped_target_met book_id=%s existing_protected=%s target=%s",
-                book_id,
-                existing_protected,
-                config.phrase_target_protected_per_book,
+        return None
+    async with AsyncSession(engine) as session:
+        if not await count_unjudged_candidates(session, source_id, config):
+            logger.info("ebook_candidate_phrase_judgment_book_skip_no_unjudged source_id=%s", source_id)
+            return None
+        existing_protected = await count_protected_phrases(session, source_id)
+        target_remaining: int | None = None
+        if config.phrase_target_protected_per_book > 0:
+            target_remaining = max(config.phrase_target_protected_per_book - existing_protected, 0)
+            if target_remaining == 0:
+                logger.info(
+                    "ebook_candidate_phrase_judgment_skipped_target_met source_id=%s existing_protected=%s target=%s",
+                    source_id,
+                    existing_protected,
+                    config.phrase_target_protected_per_book,
+                )
+                return None
+        book_text = await load_book_text(session, source_id)
+        if not book_text:
+            logger.warning("ebook_candidate_phrase_judgment_book_empty source_id=%s", source_id)
+            return None
+        normalized_book_text = normalize_text(book_text)
+        # Stored rows may predate the current junk filters and score weights, so re-filter and
+        # rescore every unjudged row here instead of trusting the persisted candidate_score.
+        rows = await load_candidates_for_judgment(session, source_id, config)
+        scored_items: list[tuple[int, PhraseCandidate]] = []
+        skipped_junk = 0
+        for row in rows:
+            candidate = phrase_candidate_from_row(row)
+            if is_junk_phrase(candidate.phrase_norm.split()):
+                skipped_junk += 1
+                continue
+            candidate.candidate_score = score_candidate(candidate, config)
+            scored_items.append((row.id, candidate))
+        scored_items.sort(key=lambda item: item[1].candidate_score, reverse=True)
+        work_items = scored_items[:judgment_limit]
+        for _, candidate in work_items:
+            candidate.sample_contexts = candidate.sample_contexts or get_sample_contexts(
+                normalized_book_text, candidate.phrase_norm
             )
-            return 0, []
-
-    rows = load_candidates_for_judgment(session, book_id, judgment_limit, config)
     logger.info(
-        "ebook_candidate_phrase_judgment_candidates_loaded book_id=%s candidates=%s existing_protected=%s "
-        "target_remaining=%s judgment_limit=%s",
-        book_id,
+        "ebook_candidate_phrase_judgment_candidates_loaded source_id=%s candidates=%s skipped_junk=%s "
+        "unjudged_rows=%s existing_protected=%s target_remaining=%s judgment_limit=%s",
+        source_id,
+        len(work_items),
+        skipped_junk,
         len(rows),
         existing_protected,
         target_remaining,
         judgment_limit,
     )
-
-    judged_count = 0
-    protected: list[EbookProtectedPhrase] = []
-    for row_number, row in enumerate(rows, start=1):
-        candidate, judgment, candidate_row = judge_candidate_row(
-            session, book_id, series_id, normalized_book_text, row, row_number, len(rows), config
-        )
-        judged_count += 1
-        if not should_protect_judged_candidate(row, candidate, judgment, book_id, config):
-            continue
-        protected.append(upsert_protected_phrase(session, book_id, series_id, candidate, judgment, candidate_row))
-        if target_remaining is not None and len(protected) >= target_remaining:
-            break
-
-    session.flush()
-    return judged_count, protected
+    return work_items, target_remaining
 
 
-def judge_candidate_row(
-    session: Session,
-    book_id: int,
-    series_id: int | None,
-    normalized_book_text: str,
-    row: EbookCandidatePhrase,
-    row_number: int,
-    total_rows: int,
+async def judge_book_candidates_async(
+    client: httpx.AsyncClient,
     config: EbookSearchConfig,
-) -> tuple[PhraseCandidate, LLMJudgment, EbookCandidatePhrase]:
-    """Run and persist the LLM judgment for a single candidate row.
+    source_id: int,
+    work_items: list[tuple[int, PhraseCandidate]],
+    target_remaining: int | None,
+) -> list[tuple[int, PhraseCandidate, LLMJudgment, bool]]:
+    """Judge a book's candidates in concurrent chunks, stopping once the target is reached.
+
+    Promotion decisions are made in memory so judging can stop early without any database writes.
 
     Args:
-        session (Session): Active database session.
-        book_id (int): Book the candidate belongs to.
-        series_id (int | None): Series scope for the saved candidate.
-        normalized_book_text (str): Whole book text, already normalized, for context lookups.
-        row (EbookCandidatePhrase): Stored candidate row to judge.
-        row_number (int): 1-based position of the row in the batch, for logging.
-        total_rows (int): Total rows in the batch, for logging.
+        client (httpx.AsyncClient): Shared async client for LLM calls.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
+        source_id (int): Book being judged, for logging.
+        work_items (list[tuple[int, PhraseCandidate]]): Candidate row ids paired with candidates,
+            in best-first score order.
+        target_remaining (int | None): Remaining protected-phrase target, or ``None`` for no cap.
 
     Returns:
-        tuple[PhraseCandidate, LLMJudgment, EbookCandidatePhrase]: The candidate, its judgment,
-        and the persisted candidate row.
+        list[tuple[int, PhraseCandidate, LLMJudgment, bool]]: Judged rows with their judgment and
+        whether each should be promoted.
     """
-    row_started_at = perf_counter()
-    candidate = phrase_candidate_from_row(row)
-    candidate.sample_contexts = row.sample_contexts or get_sample_contexts(normalized_book_text, candidate.phrase_norm)
+    chunk_size = max(1, config.phrase_judge_phrase_workers)
+    judged: list[tuple[int, PhraseCandidate, LLMJudgment, bool]] = []
+    promoted = 0
+    for start in range(0, len(work_items), chunk_size):
+        chunk = work_items[start : start + chunk_size]
+        judgments = await asyncio.gather(*(judge_candidate_async(client, config, candidate) for _, candidate in chunk))
+        for (candidate_id, candidate), judgment in zip(chunk, judgments, strict=True):
+            promote = (target_remaining is None or promoted < target_remaining) and should_protect_judged_candidate(
+                candidate, judgment, source_id, config, candidate_id=candidate_id
+            )
+            if promote:
+                promoted += 1
+            judged.append((candidate_id, candidate, judgment, promote))
+        if target_remaining is not None and promoted >= target_remaining:
+            break
+    return judged
+
+
+async def judge_candidate_async(
+    client: httpx.AsyncClient,
+    config: EbookSearchConfig,
+    candidate: PhraseCandidate,
+) -> LLMJudgment:
+    """Judge one candidate with the LLM over the shared async client.
+
+    Args:
+        client (httpx.AsyncClient): Shared async client for LLM calls.
+        config (EbookSearchConfig): Runtime phrase-tuning settings.
+        candidate (PhraseCandidate): Candidate to judge.
+
+    Returns:
+        LLMJudgment: The parsed judgment.
+    """
+    content = await request_chat_completion(client, config, build_judge_messages(candidate))
+    return parse_llm_judgment(content, config)
+
+
+async def persist_book_judgments(
+    engine: AsyncEngine,
+    source_id: int,
+    config: EbookSearchConfig,
+    judged: list[tuple[int, PhraseCandidate, LLMJudgment, bool]],
+) -> BookJudgmentResult:
+    """Persist one book's judgments and promotions in a single committed transaction.
+
+    Args:
+        engine (AsyncEngine): Engine used to open the write session.
+        source_id (int): Book being persisted.
+        config (EbookSearchConfig): Runtime phrase-tuning settings.
+        judged (list[tuple[int, PhraseCandidate, LLMJudgment, bool]]): Judged candidates with their
+            judgment and promotion flag.
+
+    Returns:
+        BookJudgmentResult: The book's committed counts, or a failed result on error.
+    """
+    book_started_at = perf_counter()
+    async with AsyncSession(engine, expire_on_commit=False) as session:
+        try:
+            protected: list[EbookProtectedPhrase] = []
+            for candidate_id, candidate, judgment, promote in judged:
+                candidate_row = await save_candidate_to_db(session, source_id, None, candidate, judgment=judgment)
+                if promote:
+                    protected.append(
+                        await upsert_protected_phrase(session, source_id, None, candidate, judgment, candidate_row)
+                    )
+                logger.info(
+                    "ebook_candidate_phrase_judgment_candidate_complete source_id=%s candidate_id=%s phrase=%r "
+                    "keep=%s confidence=%.3f category=%r promoted=%s",
+                    source_id,
+                    candidate_id,
+                    candidate.phrase_norm,
+                    judgment.keep,
+                    judgment.confidence,
+                    judgment.category,
+                    promote,
+                )
+            await session.flush()
+            mentions = await index_chunk_phrase_mentions_for_book(session, source_id, config) if protected else 0
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            logger.exception("ebook_candidate_phrase_judgment_book_persist_failed source_id=%s", source_id)
+            return BookJudgmentResult(failed=True)
     logger.info(
-        "ebook_candidate_phrase_judgment_candidate_start book_id=%s candidate_id=%s row_number=%s rows=%s "
-        "phrase=%r score=%.3f raw_count=%s chapter_count=%s",
-        book_id,
-        row.id,
-        row_number,
-        total_rows,
-        candidate.phrase_norm,
-        candidate.candidate_score,
-        candidate.raw_count,
-        candidate.chapter_count,
+        "ebook_candidate_phrase_judgment_book_committed source_id=%s judged=%s protected=%s mentions=%s "
+        "duration_ms=%.1f",
+        source_id,
+        len(judged),
+        len(protected),
+        mentions,
+        (perf_counter() - book_started_at) * 1000,
     )
-    judgment = judge_candidate_with_llm(candidate, config)
-    candidate_row = save_candidate_to_db(session, book_id, series_id, candidate, judgment=judgment)
-    logger.info(
-        "ebook_candidate_phrase_judgment_candidate_complete book_id=%s candidate_id=%s phrase=%r keep=%s "
-        "confidence=%.3f importance=%.3f category=%r duration_ms=%.1f",
-        book_id,
-        row.id,
-        candidate.phrase_norm,
-        judgment.keep,
-        judgment.confidence,
-        judgment.importance,
-        judgment.category,
-        (perf_counter() - row_started_at) * 1000,
-    )
-    return candidate, judgment, candidate_row
+    return BookJudgmentResult(judged=len(judged), protected=len(protected), mentions=mentions, committed=True)
 
 
 def should_protect_judged_candidate(
-    row: EbookCandidatePhrase,
     candidate: PhraseCandidate,
     judgment: LLMJudgment,
     book_id: int,
     config: EbookSearchConfig,
+    *,
+    candidate_id: int,
 ) -> bool:
     """Report whether a judged candidate qualifies to become a protected phrase.
 
     Args:
-        row (EbookCandidatePhrase): Stored candidate row the judgment came from.
         candidate (PhraseCandidate): In-memory candidate that was judged.
         judgment (LLMJudgment): Judge decision for the candidate.
         book_id (int): Book the candidate belongs to, for logging.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
+        candidate_id (int): Stored candidate row id the judgment came from, for logging.
 
     Returns:
         bool: True when the judged candidate should be promoted to a protected phrase.
@@ -331,25 +365,26 @@ def should_protect_judged_candidate(
     if not judgment.keep or judgment.confidence < config.protected_phrase_confidence_threshold:
         return False
     accepted_norm = normalize_text(judgment.canonical or candidate.phrase_text)
-    accepted_token_count = len(accepted_norm.split())
+    accepted_tokens = accepted_norm.split()
+    accepted_token_count = len(accepted_tokens)
     if accepted_token_count < config.phrase_min_tokens:
         logger.info(
             "ebook_candidate_phrase_judgment_candidate_skip_short_canonical book_id=%s candidate_id=%s "
             "phrase=%r canonical=%r token_count=%s min_tokens=%s",
             book_id,
-            row.id,
+            candidate_id,
             candidate.phrase_norm,
             accepted_norm,
             accepted_token_count,
             config.phrase_min_tokens,
         )
         return False
-    if is_most_common_word_phrase(accepted_norm):
+    if is_most_common_word_phrase(accepted_tokens):
         logger.info(
             "ebook_candidate_phrase_judgment_candidate_skip_common_canonical book_id=%s candidate_id=%s "
             "phrase=%r canonical=%r",
             book_id,
-            row.id,
+            candidate_id,
             candidate.phrase_norm,
             accepted_norm,
         )
@@ -357,18 +392,14 @@ def should_protect_judged_candidate(
     return True
 
 
-"""LLM judging of extracted candidate phrases."""
-
-
-def judge_candidate_with_llm(candidate: PhraseCandidate, config: EbookSearchConfig) -> LLMJudgment:
-    """Ask the configured chat model to judge one pre-extracted candidate.
+def build_judge_messages(candidate: PhraseCandidate) -> list[dict[str, str]]:
+    """Build the chat messages used to judge one candidate phrase.
 
     Args:
-        candidate (PhraseCandidate): Candidate to send to the LLM judge.
-        config (EbookSearchConfig): Runtime phrase-tuning settings and chat configuration.
+        candidate (PhraseCandidate): Candidate to describe for the judge.
 
     Returns:
-        LLMJudgment: The parsed structured judgment for the candidate.
+        list[dict[str, str]]: OpenAI-style system and user messages.
     """
     payload = {
         "phrase": candidate.phrase_norm,
@@ -378,7 +409,7 @@ def judge_candidate_with_llm(candidate: PhraseCandidate, config: EbookSearchConf
         "chapter_count": candidate.chapter_count,
         "contexts": candidate.sample_contexts,
     }
-    messages = [
+    return [
         {
             "role": "system",
             "content": (
@@ -392,7 +423,6 @@ def judge_candidate_with_llm(candidate: PhraseCandidate, config: EbookSearchConf
         },
         {"role": "user", "content": json.dumps(payload, ensure_ascii=True)},
     ]
-    return parse_llm_judgment(request_chat_completion(config, messages), config)
 
 
 def parse_llm_judgment(content: str, config: EbookSearchConfig) -> LLMJudgment:
diff --git a/python/ebook_search/protected_phrases/matching.py b/python/ebook_search/protected_phrases/matching.py
index 7fecbe3..172a852 100644
--- a/python/ebook_search/protected_phrases/matching.py
+++ b/python/ebook_search/protected_phrases/matching.py
@@ -26,7 +26,7 @@ from python.orm.richie import (
 if TYPE_CHECKING:
     from collections.abc import Iterator, Sequence
 
-    from sqlalchemy.orm import Session
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.protected_phrases.text_normalization import NormalizedToken
@@ -34,8 +34,8 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-def load_phrase_lookup(
-    session: Session,
+async def load_phrase_lookup(
+    session: AsyncSession,
     config: EbookSearchConfig,
     *,
     book_id: int | None = None,
@@ -44,7 +44,7 @@ def load_phrase_lookup(
     """Load protected phrases and aliases into RAM lookup maps.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
         book_id (int | None): Optional book scope to restrict loaded phrases.
         series_id (int | None): Optional series scope to restrict loaded phrases.
@@ -65,7 +65,7 @@ def load_phrase_lookup(
     if scope_filter is not None:
         phrase_statement = phrase_statement.where(scope_filter)
 
-    for row in session.execute(phrase_statement):
+    for row in await session.execute(phrase_statement):
         phrase_id = int(row.id)
         phrase_norm = str(row.phrase_norm)
         norm_to_ids[phrase_norm].append(phrase_id)
@@ -78,7 +78,7 @@ def load_phrase_lookup(
     if scope_filter is not None:
         alias_statement = alias_statement.where(scope_filter)
 
-    for row in session.execute(alias_statement):
+    for row in await session.execute(alias_statement):
         alias_norm = str(row.alias_norm)
         alias_to_ids[alias_norm].append(int(row.phrase_id))
         max_tokens = max(max_tokens, len(alias_norm.split()))
@@ -197,11 +197,11 @@ def detect_phrase_candidates_from_tokens(tokens_: Sequence[NormalizedToken], loo
     return matches
 
 
-def hydrate_matches(session: Session, matches: Sequence[PhraseMatch]) -> list[HydratedPhraseMatch]:
+async def hydrate_matches(session: AsyncSession, matches: Sequence[PhraseMatch]) -> list[HydratedPhraseMatch]:
     """Fetch protected phrase metadata for raw phrase matches.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         matches (Sequence[PhraseMatch]): Unhydrated matches to enrich.
 
     Returns:
@@ -216,7 +216,7 @@ def hydrate_matches(session: Session, matches: Sequence[PhraseMatch]) -> list[Hy
 
     rows = {
         row.id: row
-        for row in session.scalars(select(EbookProtectedPhrase).where(EbookProtectedPhrase.id.in_(phrase_ids)))
+        for row in await session.scalars(select(EbookProtectedPhrase).where(EbookProtectedPhrase.id.in_(phrase_ids)))
     }
     hydrated: list[HydratedPhraseMatch] = []
     for match in matches:
@@ -332,8 +332,8 @@ def resolve_overlaps(matches: Sequence[HydratedPhraseMatch]) -> list[HydratedPhr
     return kept
 
 
-def detect_protected_phrases_for_query(
-    session: Session,
+async def detect_protected_phrases_for_query(
+    session: AsyncSession,
     query_text: str,
     config: EbookSearchConfig,
     *,
@@ -344,7 +344,7 @@ def detect_protected_phrases_for_query(
     """Run the full online protected-phrase query-detection pipeline.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         query_text (str): User query text to detect phrases in.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
         lookup (PhraseLookup | None): Optional preloaded lookup; loaded on demand when ``None``.
@@ -355,13 +355,15 @@ def detect_protected_phrases_for_query(
         list[HydratedPhraseMatch]: Hydrated, overlap-resolved phrase matches for the query.
     """
     active_lookup = (
-        lookup if lookup is not None else load_phrase_lookup(session, config, book_id=book_id, series_id=series_id)
+        lookup
+        if lookup is not None
+        else await load_phrase_lookup(session, config, book_id=book_id, series_id=series_id)
     )
-    return resolve_overlaps(hydrate_matches(session, detect_phrase_candidates(query_text, active_lookup)))
+    return resolve_overlaps(await hydrate_matches(session, detect_phrase_candidates(query_text, active_lookup)))
 
 
-def index_chunk_phrase_mentions_for_book(
-    session: Session,
+async def index_chunk_phrase_mentions_for_book(
+    session: AsyncSession,
     book_id: int,
     config: EbookSearchConfig,
     *,
@@ -371,7 +373,7 @@ def index_chunk_phrase_mentions_for_book(
     """Rebuild chunk phrase mentions for all chunks in one book.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose chunk mentions are rebuilt.
         config (EbookSearchConfig): Runtime phrase-tuning settings.
         series_id (int | None): Optional series scope for lookup loading.
@@ -381,23 +383,25 @@ def index_chunk_phrase_mentions_for_book(
         int: Total number of chunk phrase mentions indexed for the book.
     """
     active_lookup = (
-        lookup if lookup is not None else load_phrase_lookup(session, config, book_id=book_id, series_id=series_id)
+        lookup
+        if lookup is not None
+        else await load_phrase_lookup(session, config, book_id=book_id, series_id=series_id)
     )
-    session.execute(delete(EbookChunkPhraseMention).where(EbookChunkPhraseMention.book_id == book_id))
-    chunks = session.scalars(select(EbookChunk).where(EbookChunk.source_id == book_id).order_by(EbookChunk.id))
+    await session.execute(delete(EbookChunkPhraseMention).where(EbookChunkPhraseMention.book_id == book_id))
+    chunks = await session.scalars(select(EbookChunk).where(EbookChunk.source_id == book_id).order_by(EbookChunk.id))
     count = 0
     for chunk in chunks:
-        count += index_chunk_phrase_mentions(session, chunk, lookup=active_lookup)
-    session.flush()
+        count += await index_chunk_phrase_mentions(session, chunk, lookup=active_lookup)
+    await session.flush()
     logger.info("ebook_chunk_phrase_mentions_indexed book_id=%s mentions=%s", book_id, count)
     return count
 
 
-def index_chunk_phrase_mentions(session: Session, chunk: EbookChunk, *, lookup: PhraseLookup) -> int:
+async def index_chunk_phrase_mentions(session: AsyncSession, chunk: EbookChunk, *, lookup: PhraseLookup) -> int:
     """Store protected phrase mentions for one chunk.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         chunk (EbookChunk): Chunk whose text is scanned for phrase mentions.
         lookup (PhraseLookup): In-memory phrase and alias lookup maps.
 
@@ -405,7 +409,7 @@ def index_chunk_phrase_mentions(session: Session, chunk: EbookChunk, *, lookup:
         int: Number of phrase mentions stored for the chunk.
     """
     raw_matches = detect_phrase_candidates_in_text(chunk.text, lookup)
-    hydrated = resolve_overlaps(hydrate_matches(session, raw_matches))
+    hydrated = resolve_overlaps(await hydrate_matches(session, raw_matches))
     for match in hydrated:
         session.add(
             EbookChunkPhraseMention(
@@ -420,8 +424,8 @@ def index_chunk_phrase_mentions(session: Session, chunk: EbookChunk, *, lookup:
     return len(hydrated)
 
 
-def phrase_hits_for_chunks(
-    session: Session,
+async def phrase_hits_for_chunks(
+    session: AsyncSession,
     *,
     chunk_ids: Sequence[int],
     phrase_ids: Sequence[int],
@@ -429,7 +433,7 @@ def phrase_hits_for_chunks(
     """Return matched protected phrases with mention counts by chunk id using indexed chunk mentions.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         chunk_ids (Sequence[int]): Chunk ids to look up mentions for.
         phrase_ids (Sequence[int]): Protected phrase ids to restrict the results to.
 
@@ -456,7 +460,7 @@ def phrase_hits_for_chunks(
         .order_by(EbookChunkPhraseMention.chunk_id, mention_count.desc(), EbookProtectedPhrase.phrase_text)
     )
     hits: defaultdict[int, list[ChunkPhraseHit]] = defaultdict(list)
-    for row in session.execute(statement):
+    for row in await session.execute(statement):
         hits[int(row.chunk_id)].append(
             ChunkPhraseHit(
                 phrase_id=int(row.phrase_id),
@@ -467,8 +471,8 @@ def phrase_hits_for_chunks(
     return {chunk_id: tuple(chunk_hits) for chunk_id, chunk_hits in hits.items()}
 
 
-def phrase_hit_counts_for_chunks(
-    session: Session,
+async def phrase_hit_counts_for_chunks(
+    session: AsyncSession,
     *,
     chunk_ids: Sequence[int],
     phrase_ids: Sequence[int],
@@ -476,12 +480,12 @@ def phrase_hit_counts_for_chunks(
     """Return phrase-hit counts by chunk id using indexed chunk mentions.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         chunk_ids (Sequence[int]): Chunk ids to count mentions for.
         phrase_ids (Sequence[int]): Protected phrase ids to restrict the counts to.
 
     Returns:
         dict[int, int]: Total mention count per chunk id.
     """
-    hits = phrase_hits_for_chunks(session, chunk_ids=chunk_ids, phrase_ids=phrase_ids)
+    hits = await phrase_hits_for_chunks(session, chunk_ids=chunk_ids, phrase_ids=phrase_ids)
     return {chunk_id: sum(hit.mention_count for hit in chunk_hits) for chunk_id, chunk_hits in hits.items()}
diff --git a/python/ebook_search/protected_phrases/models.py b/python/ebook_search/protected_phrases/models.py
index 2336fe6..36f810f 100644
--- a/python/ebook_search/protected_phrases/models.py
+++ b/python/ebook_search/protected_phrases/models.py
@@ -188,6 +188,29 @@ class PhraseCandidateGenerationResult:
     candidate_phrases: int
 
 
+@dataclass(frozen=True, slots=True)
+class CorpusPhraseStats:
+    """Corpus-wide candidate and protected phrase counts for the admin page.
+
+    Attributes:
+        total_books (int): Indexed books in the corpus.
+        books_with_candidates (int): Books that have candidate phrases generated.
+        books_fully_judged (int): Books with candidates where every candidate has been judged.
+        candidate_phrases (int): Candidate phrases stored across all books.
+        judged_candidates (int): Candidate phrases that have been LLM judged.
+        unjudged_candidates (int): Candidate phrases still waiting for judgment.
+        protected_phrases (int): Protected phrases promoted across all books.
+    """
+
+    total_books: int
+    books_with_candidates: int
+    books_fully_judged: int
+    candidate_phrases: int
+    judged_candidates: int
+    unjudged_candidates: int
+    protected_phrases: int
+
+
 @dataclass(frozen=True, slots=True)
 class PhraseJudgmentBackfillResult:
     """Summary of LLM judging for stored candidate phrases.
diff --git a/python/ebook_search/protected_phrases/pool.py b/python/ebook_search/protected_phrases/pool.py
new file mode 100644
index 0000000..68fdec4
--- /dev/null
+++ b/python/ebook_search/protected_phrases/pool.py
@@ -0,0 +1,101 @@
+"""Process pool for offloading CPU-bound phrase extraction off the request thread.
+
+Phrase extraction is pure-Python CPU work (n-gram sliding, YAKE), so running it inline in a
+sync request handler serializes concurrent recalculations behind the GIL. Submitting it to a
+``ProcessPoolExecutor`` lets concurrent extractions run in parallel across cores instead. A
+``spawn`` context is used so workers do not inherit the parent's database engine, connections,
+or server threads.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+import multiprocessing
+import os
+from concurrent.futures import ProcessPoolExecutor
+from threading import Lock
+from typing import TYPE_CHECKING
+
+from python.ebook_search.protected_phrases.extraction import extract_phrase_candidates_for_book
+
+if TYPE_CHECKING:
+    from collections.abc import Mapping, Sequence
+
+    from python.ebook_search.config import EbookSearchConfig
+    from python.ebook_search.protected_phrases.models import PhraseCandidate
+
+logger = logging.getLogger(__name__)
+
+
+class _ExtractionPool:
+    """Lazily created process-wide extraction pool and the lock guarding it."""
+
+    def __init__(self) -> None:
+        self.lock = Lock()
+        self.pool: ProcessPoolExecutor | None = None
+
+
+_extraction_pool = _ExtractionPool()
+
+
+def get_extraction_pool(max_workers: int) -> ProcessPoolExecutor:
+    """Return the shared extraction process pool, creating it on first use.
+
+    Args:
+        max_workers (int): Desired worker count; values below 1 fall back to the CPU count.
+
+    Returns:
+        ProcessPoolExecutor: The shared pool for phrase extraction.
+    """
+    with _extraction_pool.lock:
+        if _extraction_pool.pool is None:
+            workers = max_workers if max_workers > 0 else (os.cpu_count() or 1)
+            _extraction_pool.pool = ProcessPoolExecutor(
+                max_workers=workers,
+                mp_context=multiprocessing.get_context("spawn"),
+            )
+            logger.info("ebook_phrase_extraction_pool_started workers=%s", workers)
+        return _extraction_pool.pool
+
+
+def shutdown_extraction_pool() -> None:
+    """Shut down the shared extraction pool if it was started."""
+    with _extraction_pool.lock:
+        if _extraction_pool.pool is not None:
+            _extraction_pool.pool.shutdown(wait=False, cancel_futures=True)
+            _extraction_pool.pool = None
+            logger.info("ebook_phrase_extraction_pool_shutdown")
+
+
+async def extract_phrase_candidates_in_pool(
+    book_text: str,
+    chapters: Sequence[str],
+    config: EbookSearchConfig,
+    *,
+    metadata: Mapping[str, object] | None,
+) -> list[PhraseCandidate]:
+    """Run book phrase extraction in a worker process and await the result.
+
+    Only the CPU-bound extraction runs in the worker; the caller keeps all database work in the
+    request process. The spaCy pipeline is not supported here because it is not picklable, so
+    this always runs the non-spaCy extraction path.
+
+    Args:
+        book_text (str): Full book text used for extraction.
+        chapters (Sequence[str]): Chapter-like text blocks used for frequency counts.
+        config (EbookSearchConfig): Runtime phrase-tuning settings.
+        metadata (Mapping[str, object] | None): Optional book metadata used as a candidate source.
+
+    Returns:
+        list[PhraseCandidate]: Scored candidates sorted best-first and capped per book.
+    """
+    pool = get_extraction_pool(config.protected_phrase_extraction_workers)
+    future = pool.submit(
+        extract_phrase_candidates_for_book,
+        book_text,
+        list(chapters),
+        config,
+        metadata=dict(metadata) if metadata is not None else None,
+    )
+    return await asyncio.wrap_future(future)
diff --git a/python/ebook_search/protected_phrases/store.py b/python/ebook_search/protected_phrases/store.py
index 2a24f77..86aafd0 100644
--- a/python/ebook_search/protected_phrases/store.py
+++ b/python/ebook_search/protected_phrases/store.py
@@ -11,7 +11,11 @@ from sqlalchemy.dialects.postgresql import insert as pg_insert
 from sqlalchemy.dialects.sqlite import insert as sqlite_insert
 
 from python.ebook_search.protected_phrases.extraction import minimum_candidate_raw_count
-from python.ebook_search.protected_phrases.models import PhraseCandidate, PhraseRecalculationResult
+from python.ebook_search.protected_phrases.models import (
+    CorpusPhraseStats,
+    PhraseCandidate,
+    PhraseRecalculationResult,
+)
 from python.ebook_search.protected_phrases.text_normalization import normalize_text
 from python.orm.richie import (
     EbookCandidatePhrase,
@@ -27,7 +31,7 @@ if TYPE_CHECKING:
 
     from sqlalchemy.dialects.postgresql.dml import Insert as PostgresInsert
     from sqlalchemy.dialects.sqlite.dml import Insert as SqliteInsert
-    from sqlalchemy.orm import Session
+    from sqlalchemy.ext.asyncio import AsyncSession
 
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.protected_phrases.models import LLMJudgment
@@ -36,14 +40,14 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-def dialect_insert(session: Session, table: type[TableBase]) -> PostgresInsert | SqliteInsert:
+def dialect_insert(session: AsyncSession, table: type[TableBase]) -> PostgresInsert | SqliteInsert:
     """Return a dialect-specific INSERT construct that supports ``ON CONFLICT DO UPDATE``.
 
     Production runs on PostgreSQL while tests run on SQLite; both support upserts with
     compatible SQLAlchemy constructs, so the correct one is chosen from the bound dialect.
 
     Args:
-        session (Session): Active database session whose bind selects the dialect.
+        session (AsyncSession): Active database session whose bind selects the dialect.
         table (type[TableBase]): Mapped table to insert into.
 
     Returns:
@@ -54,35 +58,33 @@ def dialect_insert(session: Session, table: type[TableBase]) -> PostgresInsert |
     return pg_insert(table)
 
 
-
-
-def load_book_text(session: Session, book_id: int) -> str:
+async def load_book_text(session: AsyncSession, book_id: int) -> str:
     """Load a book's indexed chunk text as one string for phrase extraction.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose chunk text is loaded.
 
     Returns:
         str: The book's chunk text joined into a single string.
     """
-    texts = session.scalars(
+    texts = await session.scalars(
         select(EbookChunk.text).where(EbookChunk.source_id == book_id).order_by(EbookChunk.chunk_index)
     )
     return "\n\n".join(stripped for text in texts if (stripped := text.strip()))
 
 
-def load_book_chapter_texts(session: Session, book_id: int) -> list[str]:
+async def load_book_chapter_texts(session: AsyncSession, book_id: int) -> list[str]:
     """Reconstruct chapter-like text blocks from indexed chunks for phrase extraction.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose chunks are grouped into chapters.
 
     Returns:
         list[str]: Non-empty chapter-like text blocks in chunk order.
     """
-    rows = session.execute(
+    rows = await session.execute(
         select(EbookChunk.chapter_id, EbookChunk.text)
         .where(EbookChunk.source_id == book_id)
         .order_by(EbookChunk.chunk_index)
@@ -127,11 +129,11 @@ def metadata_for_source(source: EbookSource) -> dict[str, object | None]:
     }
 
 
-def metadata_for_source_id(session: Session, source_id: int) -> dict[str, object | None]:
+async def metadata_for_source_id(session: AsyncSession, source_id: int) -> dict[str, object | None]:
     """Return phrase extraction metadata for one indexed source by id.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         source_id (int): Id of the indexed source to read metadata from.
 
     Returns:
@@ -140,70 +142,128 @@ def metadata_for_source_id(session: Session, source_id: int) -> dict[str, object
     Raises:
         ValueError: If no source exists with the given id.
     """
-    source = session.get(EbookSource, source_id)
+    source = await session.get(EbookSource, source_id)
     if source is None:
         msg = f"No indexed source with id {source_id}"
         raise ValueError(msg)
     return metadata_for_source(source)
 
 
-def count_protected_phrases(session: Session, book_id: int) -> int:
+async def count_protected_phrases(session: AsyncSession, book_id: int) -> int:
     """Count stored protected phrases for one book.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose protected phrases are counted.
 
     Returns:
         int: Number of protected phrases stored for the book.
     """
-    return session.scalars(
-        select(func.count(EbookProtectedPhrase.id)).where(EbookProtectedPhrase.book_id == book_id)
+    return (
+        await session.scalars(
+            select(func.count(EbookProtectedPhrase.id)).where(EbookProtectedPhrase.book_id == book_id)
+        )
     ).one()
 
 
-def count_unjudged_candidates(session: Session, book_id: int, config: EbookSearchConfig) -> int:
+async def count_unjudged_candidates(session: AsyncSession, book_id: int, config: EbookSearchConfig) -> int:
     """Count storable candidate rows for a book that have not yet been judged.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose unjudged candidates are counted.
         config (EbookSearchConfig): Runtime phrase-tuning settings supplying storage thresholds.
 
     Returns:
         int: Number of storable, unjudged candidate rows for the book.
     """
-    return session.scalars(
-        select(func.count(EbookCandidatePhrase.id)).where(
-            EbookCandidatePhrase.book_id == book_id,
-            EbookCandidatePhrase.llm_judged.is_(False),
-            EbookCandidatePhrase.token_count >= config.phrase_min_tokens,
-            EbookCandidatePhrase.raw_count >= minimum_candidate_raw_count(config),
+    return (
+        await session.scalars(
+            select(func.count(EbookCandidatePhrase.id)).where(
+                EbookCandidatePhrase.book_id == book_id,
+                EbookCandidatePhrase.llm_judged.is_(False),
+                EbookCandidatePhrase.token_count >= config.phrase_min_tokens,
+                EbookCandidatePhrase.raw_count >= minimum_candidate_raw_count(config),
+            )
         )
     ).one()
 
 
-def load_candidates_for_judgment(
-    session: Session,
-    book_id: int,
-    judgment_limit: int,
-    config: EbookSearchConfig,
-) -> Sequence[EbookCandidatePhrase]:
-    """Load the top unjudged candidate rows for a book.
-
-    Common-word phrases are filtered before storage (``filter_storable_candidates``), so
-    no re-check is needed here.
+async def corpus_phrase_stats(session: AsyncSession) -> CorpusPhraseStats:
+    """Summarize candidate and protected phrase coverage across the whole corpus.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
+
+    Returns:
+        CorpusPhraseStats: Corpus-wide phrase counts and per-book coverage counts.
+    """
+    total_books = (await session.scalars(select(func.count(EbookSource.id)))).one()
+    candidate_phrases, judged_candidates, books_with_candidates, books_with_unjudged = (
+        await session.execute(
+            select(
+                func.count(EbookCandidatePhrase.id),
+                func.count(EbookCandidatePhrase.id).filter(EbookCandidatePhrase.llm_judged.is_(True)),
+                func.count(func.distinct(EbookCandidatePhrase.book_id)),
+                func.count(func.distinct(EbookCandidatePhrase.book_id)).filter(
+                    EbookCandidatePhrase.llm_judged.is_(False)
+                ),
+            )
+        )
+    ).one()
+    protected_phrases = (await session.scalars(select(func.count(EbookProtectedPhrase.id)))).one()
+    return CorpusPhraseStats(
+        total_books=total_books,
+        books_with_candidates=books_with_candidates,
+        books_fully_judged=books_with_candidates - books_with_unjudged,
+        candidate_phrases=candidate_phrases,
+        judged_candidates=judged_candidates,
+        unjudged_candidates=candidate_phrases - judged_candidates,
+        protected_phrases=protected_phrases,
+    )
+
+
+async def book_ids_pending_first_judgment(session: AsyncSession) -> list[int]:
+    """Return books that have candidate phrases but no judged candidates yet.
+
+    Args:
+        session (AsyncSession): Active database session.
+
+    Returns:
+        list[int]: Book ids with candidates where judging has never run, ordered by id.
+    """
+    judged_books = select(EbookCandidatePhrase.book_id).where(EbookCandidatePhrase.llm_judged.is_(True)).distinct()
+    return list(
+        (
+            await session.scalars(
+                select(EbookCandidatePhrase.book_id)
+                .where(EbookCandidatePhrase.book_id.not_in(judged_books))
+                .distinct()
+                .order_by(EbookCandidatePhrase.book_id)
+            )
+        ).all()
+    )
+
+
+async def load_candidates_for_judgment(
+    session: AsyncSession,
+    book_id: int,
+    config: EbookSearchConfig,
+) -> Sequence[EbookCandidatePhrase]:
+    """Load every storable unjudged candidate row for a book.
+
+    Rows may have been stored before the current junk filters and score weights existed, so
+    callers re-check :func:`is_junk_phrase` and rescore before selecting what to judge.
+
+    Args:
+        session (AsyncSession): Active database session.
         book_id (int): Book whose candidates are loaded.
-        judgment_limit (int): Maximum number of candidate rows to return.
         config (EbookSearchConfig): Runtime phrase-tuning settings supplying storage thresholds.
 
     Returns:
-        Sequence[EbookCandidatePhrase]: Top storable, unjudged candidate rows ordered by score.
+        Sequence[EbookCandidatePhrase]: Storable, unjudged candidate rows ordered by stored score.
     """
-    return session.scalars(
+    query = (
         select(EbookCandidatePhrase)
         .where(
             EbookCandidatePhrase.book_id == book_id,
@@ -216,8 +276,8 @@ def load_candidates_for_judgment(
             EbookCandidatePhrase.raw_count.desc(),
             EbookCandidatePhrase.id,
         )
-        .limit(judgment_limit)
-    ).all()
+    )
+    return (await session.scalars(query)).all()
 
 
 def phrase_candidate_from_row(row: EbookCandidatePhrase) -> PhraseCandidate:
@@ -248,25 +308,23 @@ def phrase_candidate_from_row(row: EbookCandidatePhrase) -> PhraseCandidate:
     )
 
 
-def save_candidate_to_db(
-    session: Session,
+def candidate_row_values(
     book_id: int,
     series_id: int | None,
     candidate: PhraseCandidate,
     *,
     judgment: LLMJudgment | None,
-) -> EbookCandidatePhrase:
-    """Insert or update one candidate phrase row.
+) -> dict[str, object]:
+    """Build the column values for one candidate phrase upsert.
 
     Args:
-        session (Session): Active database session.
         book_id (int): Book the candidate belongs to.
         series_id (int | None): Series scope stored on the row.
         candidate (PhraseCandidate): Candidate whose fields are written to the row.
         judgment (LLMJudgment | None): Judgment to record, or ``None`` to leave the row unjudged.
 
     Returns:
-        EbookCandidatePhrase: The inserted or updated candidate row.
+        dict[str, object]: Column values keyed by column name.
     """
     values: dict[str, object] = {
         "book_id": book_id,
@@ -296,6 +354,30 @@ def save_candidate_to_db(
             llm_category=judgment.category,
             llm_reason=judgment.reason,
         )
+    return values
+
+
+async def save_candidate_to_db(
+    session: AsyncSession,
+    book_id: int,
+    series_id: int | None,
+    candidate: PhraseCandidate,
+    *,
+    judgment: LLMJudgment | None,
+) -> EbookCandidatePhrase:
+    """Insert or update one candidate phrase row.
+
+    Args:
+        session (AsyncSession): Active database session.
+        book_id (int): Book the candidate belongs to.
+        series_id (int | None): Series scope stored on the row.
+        candidate (PhraseCandidate): Candidate whose fields are written to the row.
+        judgment (LLMJudgment | None): Judgment to record, or ``None`` to leave the row unjudged.
+
+    Returns:
+        EbookCandidatePhrase: The inserted or updated candidate row.
+    """
+    values = candidate_row_values(book_id, series_id, candidate, judgment=judgment)
 
     # Preserve an existing judgment when this call is only refreshing candidate fields.
     skip_update = {"book_id", "phrase_norm"}
@@ -306,11 +388,94 @@ def save_candidate_to_db(
         index_elements=["book_id", "phrase_norm"],
         set_={column: insert_statement.excluded[column] for column in values if column not in skip_update},
     ).returning(EbookCandidatePhrase)
-    return session.scalars(statement, execution_options={"populate_existing": True}).one()
+    return (await session.scalars(statement, execution_options={"populate_existing": True})).one()
 
 
-def upsert_protected_phrase(
-    session: Session,
+BULK_CANDIDATE_UPSERT_CHUNK = 1000
+
+
+async def bulk_upsert_unjudged_candidates(
+    session: AsyncSession,
+    book_id: int,
+    series_id: int | None,
+    candidates: Sequence[PhraseCandidate],
+) -> int:
+    """Insert or update many freshly extracted candidate rows in chunked multi-row upserts.
+
+    Saving one row per statement costs one database round trip per candidate, which dominated
+    generation time for full books, so candidates are written ``BULK_CANDIDATE_UPSERT_CHUNK``
+    rows per statement instead. Existing judgments and sample contexts are never overwritten:
+    fresh extractions carry no contexts, and ``llm_judged`` plus the ``llm_*`` columns are left
+    out of the conflict update. Candidates must have unique ``phrase_norm`` values, as produced
+    by extraction, since one multi-row upsert cannot touch the same row twice.
+
+    Args:
+        session (Session): Active database session.
+        book_id (int): Book the candidates belong to.
+        series_id (int | None): Series scope stored on the rows.
+        candidates (Sequence[PhraseCandidate]): Freshly extracted candidates to persist.
+
+    Returns:
+        int: Number of candidate rows written.
+    """
+    values = [
+        candidate_row_values(book_id, series_id, candidate, judgment=None)
+        for candidate in candidates
+        if not candidate.sample_contexts
+    ]
+    if len(values) != len(candidates):
+        msg = "bulk_upsert_unjudged_candidates only accepts freshly extracted candidates without sample contexts"
+        raise ValueError(msg)
+    skip_update = {"book_id", "phrase_norm", "llm_judged"}
+    for chunk_start in range(0, len(values), BULK_CANDIDATE_UPSERT_CHUNK):
+        chunk = values[chunk_start : chunk_start + BULK_CANDIDATE_UPSERT_CHUNK]
+        insert_statement = dialect_insert(session, EbookCandidatePhrase).values(chunk)
+        statement = insert_statement.on_conflict_do_update(
+            index_elements=["book_id", "phrase_norm"],
+            set_={column: insert_statement.excluded[column] for column in chunk[0] if column not in skip_update},
+        )
+        await session.execute(statement)
+    return len(values)
+
+
+def new_candidate_row(book_id: int, series_id: int | None, candidate: PhraseCandidate) -> EbookCandidatePhrase:
+    """Build a fresh unjudged candidate row without checking for an existing one.
+
+    Unlike :func:`save_candidate_to_db`, this does no lookup, so it is only safe when the caller
+    guarantees there is no existing row for ``(book_id, candidate.phrase_norm)`` — for example
+    right after :func:`delete_phrase_data_for_book` has cleared the book.
+
+    Args:
+        book_id (int): Book the candidate belongs to.
+        series_id (int | None): Series scope stored on the row.
+        candidate (PhraseCandidate): Candidate whose fields are written to the row.
+
+    Returns:
+        EbookCandidatePhrase: A new, unattached candidate row.
+    """
+    row = EbookCandidatePhrase(book_id=book_id, phrase_norm=candidate.phrase_norm)
+    row.llm_judged = False
+    row.series_id = series_id
+    row.phrase_text = candidate.phrase_text
+    row.token_count = candidate.token_count
+    row.source_raw_ngram = candidate.source_raw_ngram
+    row.source_yake = candidate.source_yake
+    row.source_spacy_ner = candidate.source_spacy_ner
+    row.source_spacy_noun_chunk = candidate.source_spacy_noun_chunk
+    row.source_capitalized = candidate.source_capitalized
+    row.source_metadata = candidate.source_metadata
+    row.spacy_label = candidate.spacy_label
+    row.raw_count = candidate.raw_count
+    row.chapter_count = candidate.chapter_count
+    row.yake_score = candidate.yake_score
+    row.candidate_score = candidate.candidate_score
+    if candidate.sample_contexts:
+        row.sample_contexts = list(candidate.sample_contexts)
+    return row
+
+
+async def upsert_protected_phrase(
+    session: AsyncSession,
     book_id: int,
     series_id: int | None,
     candidate: PhraseCandidate,
@@ -320,7 +485,7 @@ def upsert_protected_phrase(
     """Insert or update one accepted protected phrase and its aliases.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book the protected phrase belongs to.
         series_id (int | None): Series scope stored on the phrase.
         candidate (PhraseCandidate): Candidate the phrase was promoted from.
@@ -360,18 +525,22 @@ def upsert_protected_phrase(
             column: insert_statement.excluded[column] for column in values if column not in {"book_id", "phrase_norm"}
         },
     ).returning(EbookProtectedPhrase)
-    row = session.scalars(statement, execution_options={"populate_existing": True}).one()
+    row = (await session.scalars(statement, execution_options={"populate_existing": True})).one()
 
     for alias_text in judgment.aliases:
-        upsert_phrase_alias(session, row, alias_text)
+        await upsert_phrase_alias(session, row, alias_text)
     return row
 
 
-def upsert_phrase_alias(session: Session, phrase: EbookProtectedPhrase, alias_text: str) -> EbookPhraseAlias | None:
+async def upsert_phrase_alias(
+    session: AsyncSession,
+    phrase: EbookProtectedPhrase,
+    alias_text: str,
+) -> EbookPhraseAlias | None:
     """Insert or update one protected phrase alias.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         phrase (EbookProtectedPhrase): Protected phrase the alias points to.
         alias_text (str): Alias surface form to store.
 
@@ -395,7 +564,7 @@ def upsert_phrase_alias(session: Session, phrase: EbookProtectedPhrase, alias_te
             "confidence": insert_statement.excluded.confidence,
         },
     ).returning(EbookPhraseAlias)
-    return session.scalars(statement, execution_options={"populate_existing": True}).one()
+    return (await session.scalars(statement, execution_options={"populate_existing": True})).one()
 
 
 def make_canonical_id(judgment: LLMJudgment, phrase_norm: str) -> str:
@@ -426,15 +595,15 @@ def slugify_identifier(value: str) -> str:
     return slug.strip("_") or "unknown"
 
 
-def prune_unstorable_unjudged_candidate_phrases(
-    session: Session,
+async def prune_unstorable_unjudged_candidate_phrases(
+    session: AsyncSession,
     book_id: int,
     config: EbookSearchConfig,
 ) -> int:
     """Delete old unjudged candidate rows that no longer satisfy storage filters.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose stale candidates are pruned.
         config (EbookSearchConfig): Runtime phrase-tuning settings supplying storage thresholds.
 
@@ -442,7 +611,7 @@ def prune_unstorable_unjudged_candidate_phrases(
         int: Number of candidate rows deleted.
     """
     deleted = rowcount(
-        session.execute(
+        await session.execute(
             delete(EbookCandidatePhrase).where(
                 EbookCandidatePhrase.book_id == book_id,
                 EbookCandidatePhrase.llm_judged.is_(False),
@@ -464,40 +633,42 @@ def prune_unstorable_unjudged_candidate_phrases(
     return deleted
 
 
-def delete_phrase_data_for_book(session: Session, book_id: int) -> PhraseRecalculationResult:
+async def delete_phrase_data_for_book(session: AsyncSession, book_id: int) -> PhraseRecalculationResult:
     """Delete all candidate, protected, alias, and mention phrase data for one book.
 
     Args:
-        session (Session): Active database session.
+        session (AsyncSession): Active database session.
         book_id (int): Book whose phrase data is deleted.
 
     Returns:
         PhraseRecalculationResult: Deleted-row counts with ``candidate_phrases`` set to 0.
     """
-    protected_ids = session.scalars(
-        select(EbookProtectedPhrase.id).where(EbookProtectedPhrase.book_id == book_id)
+    protected_ids = (
+        await session.scalars(select(EbookProtectedPhrase.id).where(EbookProtectedPhrase.book_id == book_id))
     ).all()
     deleted_aliases = 0
     if protected_ids:
         deleted_aliases = rowcount(
-            session.execute(delete(EbookPhraseAlias).where(EbookPhraseAlias.phrase_id.in_(protected_ids)))
+            await session.execute(delete(EbookPhraseAlias).where(EbookPhraseAlias.phrase_id.in_(protected_ids)))
         )
 
     deleted_mentions = rowcount(
-        session.execute(delete(EbookChunkPhraseMention).where(EbookChunkPhraseMention.book_id == book_id))
+        await session.execute(delete(EbookChunkPhraseMention).where(EbookChunkPhraseMention.book_id == book_id))
     )
     if protected_ids:
         deleted_mentions += rowcount(
-            session.execute(delete(EbookChunkPhraseMention).where(EbookChunkPhraseMention.phrase_id.in_(protected_ids)))
+            await session.execute(
+                delete(EbookChunkPhraseMention).where(EbookChunkPhraseMention.phrase_id.in_(protected_ids))
+            )
         )
 
     deleted_protected = rowcount(
-        session.execute(delete(EbookProtectedPhrase).where(EbookProtectedPhrase.book_id == book_id))
+        await session.execute(delete(EbookProtectedPhrase).where(EbookProtectedPhrase.book_id == book_id))
     )
     deleted_candidates = rowcount(
-        session.execute(delete(EbookCandidatePhrase).where(EbookCandidatePhrase.book_id == book_id))
+        await session.execute(delete(EbookCandidatePhrase).where(EbookCandidatePhrase.book_id == book_id))
     )
-    session.flush()
+    await session.flush()
     logger.info(
         "ebook_candidate_phrase_data_deleted book_id=%s candidates=%s protected=%s aliases=%s mentions=%s",
         book_id,
@@ -515,6 +686,7 @@ def delete_phrase_data_for_book(session: Session, book_id: int) -> PhraseRecalcu
         candidate_phrases=0,
     )
 
+
 def rowcount(result: object) -> int:
     """Return a safe integer rowcount from a SQLAlchemy execution result.
 
diff --git a/python/ebook_search/rerank.py b/python/ebook_search/rerank.py
index 05354be..b47e5ec 100644
--- a/python/ebook_search/rerank.py
+++ b/python/ebook_search/rerank.py
@@ -9,6 +9,8 @@ from typing import TYPE_CHECKING
 from python.ebook_search.llm_interface import request_rerank
 
 if TYPE_CHECKING:
+    import httpx
+
     from python.ebook_search.config import RerankConfig
     from python.ebook_search.search import SearchResult
 
@@ -23,7 +25,12 @@ class RerankResult:
     score: float
 
 
-def rerank_chunks(query: str, candidates: list[SearchResult], config: RerankConfig) -> list[SearchResult]:
+async def rerank_chunks(
+    client: httpx.AsyncClient,
+    query: str,
+    candidates: list[SearchResult],
+    config: RerankConfig,
+) -> list[SearchResult]:
     """Rerank candidates with a vLLM rerank endpoint."""
     if not candidates:
         return []
@@ -34,7 +41,7 @@ def rerank_chunks(query: str, candidates: list[SearchResult], config: RerankConf
         config.model,
         len(candidates),
     )
-    scores = score_candidates(query, candidates, config)
+    scores = await score_candidates(client, query, candidates, config)
     results = sorted(
         (
             replace(
@@ -56,13 +63,14 @@ def rerank_chunks(query: str, candidates: list[SearchResult], config: RerankConf
     return results
 
 
-def score_candidates(
+async def score_candidates(
+    client: httpx.AsyncClient,
     query: str,
     candidates: list[SearchResult],
     config: RerankConfig,
 ) -> dict[int, RerankResult]:
     """Score candidate chunks with the configured rerank API."""
-    body = request_rerank(query, [candidate.text for candidate in candidates], config)
+    body = await request_rerank(client, query, [candidate.text for candidate in candidates], config)
     if body is None:
         return zero_rerank_scores(candidates)
 
diff --git a/python/ebook_search/search.py b/python/ebook_search/search.py
index c59f87a..d8a5709 100644
--- a/python/ebook_search/search.py
+++ b/python/ebook_search/search.py
@@ -2,17 +2,17 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
 import re
 from collections import defaultdict
-from concurrent.futures import ThreadPoolExecutor
 from dataclasses import dataclass, replace
 from typing import TYPE_CHECKING
 
 from pgvector.sqlalchemy import Vector
 from sqlalchemy import literal, select
 from sqlalchemy.exc import SQLAlchemyError
-from sqlalchemy.orm import Session
+from sqlalchemy.ext.asyncio import AsyncSession
 
 from python.ebook_search.bm25_corpus import (
     BM25CorpusUnavailableError,
@@ -25,7 +25,7 @@ from python.ebook_search.protected_phrases.matching import (
     phrase_hits_for_chunks,
 )
 from python.ebook_search.rerank import rerank_chunks
-from python.ebook_search.timing import RuntimeStep, timed_result
+from python.ebook_search.timing import RuntimeStep, async_timed_result, timed_result
 from python.orm.richie import (
     EbookChapter,
     EbookChunk,
@@ -36,7 +36,8 @@ from python.orm.richie import (
 if TYPE_CHECKING:
     from collections.abc import Mapping, Sequence
 
-    from sqlalchemy.engine import Engine
+    import httpx
+    from sqlalchemy.ext.asyncio import AsyncEngine
 
     from python.ebook_search.config import EbookSearchConfig
     from python.ebook_search.protected_phrases.models import HydratedPhraseMatch
@@ -90,8 +91,9 @@ class RetrievalResponse:
     timings: tuple[RuntimeStep, ...]
 
 
-def search_ebooks(
-    engine: Engine,
+async def search_ebooks(
+    engine: AsyncEngine,
+    client: httpx.AsyncClient,
     query: str,
     config: EbookSearchConfig,
     *,
@@ -112,16 +114,15 @@ def search_ebooks(
     )
     timings: list[RuntimeStep] = []
     if phrase_matching_enabled:
-        phrase_matches, timing = timed_result("Protected phrase detection", query_phrase_matches, engine, query, config)
+        phrase_matches, timing = await async_timed_result(
+            "Protected phrase detection", query_phrase_matches(engine, query, config)
+        )
     else:
         phrase_matches, timing = timed_result("Protected phrase detection skipped", skip_phrase_matches)
     timings.append(timing)
-    retrieval, timing = timed_result(
+    retrieval, timing = await async_timed_result(
         "Hybrid retrieval",
-        parallel_retrieval,
-        engine,
-        query,
-        config,
+        parallel_retrieval(engine, client, query, config),
     )
     timings.extend(retrieval.timings)
     timings.append(timing)
@@ -134,19 +135,15 @@ def search_ebooks(
     )
     timings.append(timing)
     if phrase_matching_enabled:
-        fused, timing = timed_result(
+        fused, timing = await async_timed_result(
             "Phrase mention boost",
-            apply_phrase_mention_boosts,
-            engine,
-            fused,
-            phrase_matches,
-            config.phrase_hit_boost,
+            apply_phrase_mention_boosts(engine, fused, phrase_matches, config.phrase_hit_boost),
         )
     else:
         fused, timing = timed_result("Phrase mention boost skipped", skip_phrase_mention_boosts, fused)
     timings.append(timing)
     if config.rerank.enabled and rerank:
-        response, timing = timed_result("Rerank", apply_rerank, query, fused, config)
+        response, timing = await async_timed_result("Rerank", apply_rerank(client, query, fused, config))
     else:
         response, timing = timed_result("Rerank skipped", skip_rerank, query, fused, config)
     timings.append(timing)
@@ -172,11 +169,15 @@ def skip_phrase_matches() -> list[HydratedPhraseMatch]:
     return []
 
 
-def query_phrase_matches(engine: Engine, query: str, config: EbookSearchConfig) -> list[HydratedPhraseMatch]:
+async def query_phrase_matches(
+    engine: AsyncEngine,
+    query: str,
+    config: EbookSearchConfig,
+) -> list[HydratedPhraseMatch]:
     """Detect protected phrases in a query without making search fail when phrase tables are unavailable."""
     try:
-        with Session(engine) as session:
-            return detect_protected_phrases_for_query(session, query, config)
+        async with AsyncSession(engine) as session:
+            return await detect_protected_phrases_for_query(session, query, config)
     except SQLAlchemyError as error:
         logger.warning("ebook_protected_phrase_detection_unavailable error=%s", error)
         return []
@@ -188,8 +189,8 @@ def skip_phrase_mention_boosts(candidates: list[SearchResult]) -> list[SearchRes
     return candidates
 
 
-def apply_phrase_mention_boosts(
-    engine: Engine,
+async def apply_phrase_mention_boosts(
+    engine: AsyncEngine,
     candidates: list[SearchResult],
     phrase_matches: Sequence[HydratedPhraseMatch],
     phrase_hit_boost: float,
@@ -201,8 +202,8 @@ def apply_phrase_mention_boosts(
 
     chunk_ids = [candidate.chunk_id for candidate in candidates]
     try:
-        with Session(engine) as session:
-            phrase_hits = phrase_hits_for_chunks(session, chunk_ids=chunk_ids, phrase_ids=phrase_ids)
+        async with AsyncSession(engine) as session:
+            phrase_hits = await phrase_hits_for_chunks(session, chunk_ids=chunk_ids, phrase_ids=phrase_ids)
     except SQLAlchemyError as error:
         logger.warning("ebook_phrase_boost_unavailable error=%s", error)
         return candidates
@@ -241,30 +242,21 @@ def phrase_rank_source(rank_source: str, phrase_hit_count: int) -> str:
     return f"{rank_source} + phrases"
 
 
-def parallel_retrieval(
-    engine: Engine,
+async def parallel_retrieval(
+    engine: AsyncEngine,
+    client: httpx.AsyncClient,
     query: str,
     config: EbookSearchConfig,
 ) -> RetrievalResponse:
-    """Run vector and BM25 candidate retrieval concurrently with separate database sessions."""
-    with ThreadPoolExecutor(max_workers=2, thread_name_prefix="ebook-search") as executor:
-        vector_future = executor.submit(
-            timed_result,
-            "Embedding + vector search",
-            vector_candidates,
-            engine,
-            query,
-            config,
-        )
-        bm25_future = executor.submit(
-            timed_result,
-            "BM25 search",
-            bm25_candidates,
-            query,
-            config,
-        )
-        vector_results, vector_timing = vector_future.result()
-        lexical_results, lexical_timing = bm25_future.result()
+    """Run vector and BM25 candidate retrieval concurrently with separate database sessions.
+
+    BM25 scoring is pure CPU work over the cached corpus, so it runs in a worker thread
+    instead of on the event loop.
+    """
+    (vector_results, vector_timing), (lexical_results, lexical_timing) = await asyncio.gather(
+        async_timed_result("Embedding + vector search", vector_candidates(engine, client, query, config)),
+        async_timed_result("BM25 search", asyncio.to_thread(bm25_candidates, query, config)),
+    )
 
     logger.info(
         "ebook_parallel_retrieval_complete vector_candidates=%s lexical_candidates=%s",
@@ -291,13 +283,14 @@ def skip_rerank(
     return SearchResponse(query=query, results=candidates[: config.top_k], rank_label="Hybrid")
 
 
-def apply_rerank(
+async def apply_rerank(
+    client: httpx.AsyncClient,
     query: str,
     candidates: list[SearchResult],
     config: EbookSearchConfig,
 ) -> SearchResponse:
     """Rerank already-fused hybrid candidates."""
-    reranked = rerank_chunks(query, candidates[: config.rerank.candidates], config.rerank)
+    reranked = await rerank_chunks(client, query, candidates[: config.rerank.candidates], config.rerank)
     logger.info(
         "ebook_rerank_complete input_candidates=%s returned=%s",
         min(len(candidates), config.rerank.candidates),
@@ -310,10 +303,17 @@ def apply_rerank(
     )
 
 
-def vector_candidates(engine: Engine, query: str, config: EbookSearchConfig) -> list[SearchResult]:
+async def vector_candidates(
+    engine: AsyncEngine,
+    client: httpx.AsyncClient,
+    query: str,
+    config: EbookSearchConfig,
+) -> list[SearchResult]:
     """Return pgvector cosine candidates for a natural-language query."""
-    with Session(engine) as session:
-        model = session.scalar(select(EbookEmbeddingModel).where(EbookEmbeddingModel.name == config.embedding_model))
+    async with AsyncSession(engine) as session:
+        model = await session.scalar(
+            select(EbookEmbeddingModel).where(EbookEmbeddingModel.name == config.embedding_model)
+        )
         if model is None:
             msg = f"Embedding model is not registered: {config.embedding_model}"
             raise ValueError(msg)
@@ -323,7 +323,7 @@ def vector_candidates(engine: Engine, query: str, config: EbookSearchConfig) ->
             msg = f"Model row dimension {model.dimension} does not match configured dimension {expected_dimension}"
             raise ValueError(msg)
 
-        embedding = embed_query(query, config)
+        embedding = await embed_query(client, query, config)
         limit = max(config.rerank.candidates, config.top_k) * config.vector_candidate_multiplier
         embedding_table = get_embedding_table(model.dimension)
 
@@ -349,7 +349,7 @@ def vector_candidates(engine: Engine, query: str, config: EbookSearchConfig) ->
             .order_by(distance)
             .limit(limit)
         )
-        rows = session.execute(statement).mappings()
+        rows = (await session.execute(statement)).mappings()
         results = [search_result_from_row(row) for row in rows]
         logger.info(
             "ebook_vector_search_complete model=%s dimension=%s candidates=%s",
diff --git a/python/ebook_search/timing.py b/python/ebook_search/timing.py
index eb8e474..9dff9a6 100644
--- a/python/ebook_search/timing.py
+++ b/python/ebook_search/timing.py
@@ -7,7 +7,7 @@ from time import perf_counter
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
-    from collections.abc import Callable
+    from collections.abc import Awaitable, Callable
 
 
 @dataclass(frozen=True)
@@ -34,3 +34,10 @@ def timed_result[T, **P](
     start_seconds = perf_counter()
     result = operation(*args, **kwargs)
     return result, runtime_step_from_start(name, start_seconds)
+
+
+async def async_timed_result[T](name: str, awaitable: Awaitable[T]) -> tuple[T, RuntimeStep]:
+    """Await an operation and return its result plus elapsed runtime."""
+    start_seconds = perf_counter()
+    result = await awaitable
+    return result, runtime_step_from_start(name, start_seconds)
diff --git a/python/fastapi_tools/__init__.py b/python/fastapi_tools/__init__.py
index d55eb3d..8490ccb 100644
--- a/python/fastapi_tools/__init__.py
+++ b/python/fastapi_tools/__init__.py
@@ -1,6 +1,6 @@
 """Reusable FastAPI tools."""
 
-from python.fastapi_tools.db import DbSession, get_db
+from python.fastapi_tools.db import AsyncDbSession, DbSession, get_async_db, get_db
 from python.fastapi_tools.zstd_middleware import ZstdMiddleware
 
-__all__ = ["DbSession", "ZstdMiddleware", "get_db"]
+__all__ = ["AsyncDbSession", "DbSession", "ZstdMiddleware", "get_async_db", "get_db"]
diff --git a/python/fastapi_tools/db.py b/python/fastapi_tools/db.py
index c6ee685..6dad25a 100644
--- a/python/fastapi_tools/db.py
+++ b/python/fastapi_tools/db.py
@@ -5,10 +5,11 @@ from __future__ import annotations
 from typing import TYPE_CHECKING, Annotated
 
 from fastapi import Depends, Request
+from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import Session
 
 if TYPE_CHECKING:
-    from collections.abc import Iterator
+    from collections.abc import AsyncIterator, Iterator
 
 
 def get_db(request: Request) -> Iterator[Session]:
@@ -17,4 +18,15 @@ def get_db(request: Request) -> Iterator[Session]:
         yield session
 
 
+async def get_async_db(request: Request) -> AsyncIterator[AsyncSession]:
+    """Get an async database session from app state.
+
+    expire_on_commit=False keeps ORM attributes readable after commit without
+    triggering implicit IO, which would raise under asyncio.
+    """
+    async with AsyncSession(request.app.state.engine, expire_on_commit=False) as session:
+        yield session
+
+
 DbSession = Annotated[Session, Depends(get_db)]
+AsyncDbSession = Annotated[AsyncSession, Depends(get_async_db)]
diff --git a/python/orm/common.py b/python/orm/common.py
index 2b42564..fcf7da4 100644
--- a/python/orm/common.py
+++ b/python/orm/common.py
@@ -7,6 +7,7 @@ from typing import cast
 
 from sqlalchemy import create_engine
 from sqlalchemy.engine import URL, Engine
+from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine
 
 NAMING_CONVENTION = {
     "ix": "ix_%(table_name)s_%(column_0_name)s",
@@ -31,6 +32,36 @@ def get_connection_info(name: str) -> tuple[str, str, str, str, str | None]:
     return cast("tuple[str, str, str, str, str | None]", (database, host, port, username, password))
 
 
+def build_postgres_url(name: str, *, vector_engine: bool = False) -> tuple[URL, dict[str, str]]:
+    """Build the Postgres connection URL and connect_args from environment variables.
+
+    Args:
+        name (str): The name of the environment variable prefix.
+        vector_engine (bool, optional): Whether to use the vector search schema. Defaults to False.
+        This updates the search path to include the vector types and operators.
+
+    Returns:
+        tuple[URL, dict[str, str]]: The SQLAlchemy URL and connect_args for create_engine.
+    """
+    database, host, port, username, password = get_connection_info(name)
+
+    url = URL.create(
+        drivername="postgresql+psycopg",
+        username=username,
+        password=password,
+        host=host,
+        port=int(port),
+        database=database,
+    )
+
+    connect_args = {}
+    # There more better way to do this is with separate PG account and a dedicated vector schema for the vector types
+    if vector_engine:
+        connect_args["options"] = "-csearch_path=main,public"
+
+    return url, connect_args
+
+
 def get_postgres_engine(
     *,
     name: str = "POSTGRES",
@@ -51,21 +82,7 @@ def get_postgres_engine(
     Returns:
         Engine: The SQLAlchemy engine.
     """
-    database, host, port, username, password = get_connection_info(name)
-
-    url = URL.create(
-        drivername="postgresql+psycopg",
-        username=username,
-        password=password,
-        host=host,
-        port=int(port),
-        database=database,
-    )
-
-    connect_args = {}
-    # There more better way to do this is with separate PG account and a dedicated vector schema for the vector types
-    if vector_engine:
-        connect_args["options"] = "-csearch_path=main,public"
+    url, connect_args = build_postgres_url(name, vector_engine=vector_engine)
 
     return create_engine(
         url=url,
@@ -74,3 +91,34 @@ def get_postgres_engine(
         connect_args=connect_args,
         pool_size=pool_size,
     )
+
+
+def get_async_postgres_engine(
+    *,
+    name: str = "POSTGRES",
+    pool_pre_ping: bool = True,
+    vector_engine: bool = False,
+    pool_size: int = 8,
+) -> AsyncEngine:
+    """Create an async SQLAlchemy engine from environment variables.
+
+    Args:
+        name (str, optional): The name of the environment variable prefix. Defaults to "POSTGRES".
+        pool_pre_ping (bool, optional): Whether to ping the database before each connection. Defaults to True.
+        This fixes the issue of trying to use a conection that has timed out on the database side.
+        vector_engine (bool, optional): Whether to use the vector search schema. Defaults to False.
+        This updates the search path the incldued the vecore types and operators.
+        pool_size (int, optional): Number of connections to keep in the pool. Defaults to 8.
+
+    Returns:
+        AsyncEngine: The async SQLAlchemy engine.
+    """
+    url, connect_args = build_postgres_url(name, vector_engine=vector_engine)
+
+    return create_async_engine(
+        url=url,
+        pool_pre_ping=pool_pre_ping,
+        pool_recycle=1800,
+        connect_args=connect_args,
+        pool_size=pool_size,
+    )