diff --git a/static/app.js b/static/app.js
index 7bcadde..3dbe386 100644
--- a/static/app.js
+++ b/static/app.js
@@ -126,6 +126,7 @@ async function loadLibraries() {
         <td>${l.language ? esc(languageName(l.language)) : "—"}</td>
         <td class="row">
           <button class="secondary" data-edit-lib="${l.id}">${t("common.edit")}</button>
+          <button class="secondary" data-adopt-lib="${l.id}" title="${esc(t("adopt.buttonTitle"))}">${t("adopt.button")}</button>
           <button class="danger" data-del-lib="${l.id}">${t("common.delete")}</button>
         </td>
       </tr>`
@@ -134,6 +135,9 @@ async function loadLibraries() {
   tbody.querySelectorAll("[data-edit-lib]").forEach((b) =>
     b.addEventListener("click", () => startLibraryEdit(parseInt(b.dataset.editLib)))
   );
+  tbody.querySelectorAll("[data-adopt-lib]").forEach((b) =>
+    b.addEventListener("click", () => openAdopt(parseInt(b.dataset.adoptLib)))
+  );
   tbody.querySelectorAll("[data-del-lib]").forEach((b) =>
     b.addEventListener("click", async () => {
       if (!confirm(t("lib.confirmDelete"))) return;
@@ -664,7 +668,7 @@ $("#missing-bulk-delete").addEventListener("click", () => bulkDeleteRequests("mi
 
 // ---- activity ----
 let historyRows = [];
-const HISTORY_STATE = { imported: "done", appended: "done", failed: "failed" };
+const HISTORY_STATE = { imported: "done", appended: "done", adopted: "done", failed: "failed" };
 
 async function loadHistory() {
   try {
@@ -1818,6 +1822,75 @@ function setImportProgress(done, total) {
     `${done}/${total} · ${Math.round((done / total) * 100)} %`;
 }
 
+// ---- adopt files already in a library ----
+let adoptLib = null;
+let adoptScan = null;
+
+async function openAdopt(id) {
+  adoptLib = libraries.find((l) => l.id === id);
+  adoptScan = null;
+  $("#adopt-heading").textContent = t("adopt.heading", { name: adoptLib.name });
+  $("#adopt-intro").innerHTML = `<span class="spinner"></span> ${t("import.scanning")}`;
+  $("#adopt-list").innerHTML = "";
+  $("#adopt-submit").disabled = true;
+  $("#adopt-dialog").showModal();
+  try {
+    adoptScan = await api("/api/import/library/" + id);
+  } catch (err) {
+    $("#adopt-intro").textContent = "";
+    toast(err.message, true);
+    return;
+  }
+  renderAdopt();
+}
+
+function renderAdopt() {
+  if (!adoptScan) return;
+  // only files with a suggestion: a select per unmatched file would bury them
+  const matched = adoptScan.items.filter((i) => i.suggested_request_id);
+  $("#adopt-intro").textContent = t("adopt.intro", {
+    n: matched.length, rest: adoptScan.items.length - matched.length,
+  });
+  const options = adoptScan.requests
+    .map((r) => [r.id, r.authors ? `${r.authors}: ${r.title}` : r.title]);
+  $("#adopt-list").innerHTML = matched
+    .map((item) => `<label>
+        <input type="checkbox" checked data-adopt-path="${esc(item.path)}" />
+        <span>${esc(item.name)} <span class="muted">${esc(item.rel_dir)}</span></span>
+        <select>${options.map(([id, label]) =>
+          `<option value="${id}"${id === item.suggested_request_id ? " selected" : ""}>${esc(label)}</option>`
+        ).join("")}</select>
+      </label>`)
+    .join("");
+  $("#adopt-submit").disabled = matched.length === 0;
+}
+
+$("#adopt-cancel").addEventListener("click", () => $("#adopt-dialog").close());
+
+$("#adopt-submit").addEventListener("click", async () => {
+  const items = [...$$("#adopt-list [data-adopt-path]:checked")].map((box) => ({
+    path: box.dataset.adoptPath,
+    request_id: parseInt(box.closest("label").querySelector("select").value),
+  }));
+  if (!items.length) return;
+  $("#adopt-submit").disabled = true;
+  try {
+    const { results } = await api("/api/import/library/" + adoptLib.id, {
+      method: "POST", body: JSON.stringify({ items }),
+    });
+    const failed = results.filter((r) => !r.ok);
+    toast(failed.length
+      ? t("adopt.partial", { n: results.length - failed.length, failed: failed.map((r) => `${r.path}: ${r.error}`).join("; ") })
+      : t("adopt.done", { n: results.length }), failed.length > 0);
+    $("#adopt-dialog").close();
+    refreshMissingBadge();
+  } catch (err) {
+    toast(err.message, true);
+  } finally {
+    $("#adopt-submit").disabled = false;
+  }
+});
+
 // ---- language ----
 function updateLangButton() {
   $("#lang-toggle").textContent = lang === "de" ? "EN" : "DE";
@@ -1836,6 +1909,7 @@ function onLangChange() {
   const editId = $("#lib-form").dataset.editId;
   editId ? startLibraryEdit(parseInt(editId)) : endLibraryEdit();
   if (scanItems.length) renderImportTable();
+  renderAdopt();
 }
 
 // ---- version ----
diff --git a/static/i18n.js b/static/i18n.js
index 745278b..14bb8dc 100644
--- a/static/i18n.js
+++ b/static/i18n.js
@@ -56,6 +56,14 @@ const STRINGS = {
     "history.retagged": "neu getaggt",
     "history.deleted": "gelöscht",
     "history.failed": "fehlgeschlagen",
+    "history.adopted": "übernommen",
+    "adopt.button": "Einlesen",
+    "adopt.buttonTitle": "Dateien, die schon in der Library liegen, offenen Anfragen zuordnen",
+    "adopt.heading": "„{name}“ einlesen",
+    "adopt.intro": "{n} Dateien passen zu offenen Anfragen dieser Library und bleiben, wo sie sind. {rest} weitere ohne Treffer.",
+    "adopt.submit": "Übernehmen",
+    "adopt.done": "{n} übernommen",
+    "adopt.partial": "{n} übernommen, Fehler: {failed}",
 
     "search.languageTitle": "Sprache der Ausgabe — filtert Ebook- und Audiobook-Suche",
     "search.allLanguages": "Alle Sprachen",
@@ -296,6 +304,14 @@ const STRINGS = {
     "history.retagged": "retagged",
     "history.deleted": "deleted",
     "history.failed": "failed",
+    "history.adopted": "adopted",
+    "adopt.button": "Scan",
+    "adopt.buttonTitle": "Link files already in the library to open requests",
+    "adopt.heading": "Scan “{name}”",
+    "adopt.intro": "{n} files match open requests of this library and stay where they are. {rest} more without a match.",
+    "adopt.submit": "Adopt",
+    "adopt.done": "{n} adopted",
+    "adopt.partial": "{n} adopted, errors: {failed}",
 
     "search.languageTitle": "Edition language — filters the ebook and audiobook search",
     "search.allLanguages": "All languages",
diff --git a/static/index.html b/static/index.html
index 73331d6..b92f1ca 100644
--- a/static/index.html
+++ b/static/index.html
@@ -379,6 +379,16 @@
       </form>
     </dialog>
 
+    <dialog id="adopt-dialog">
+      <h3 id="adopt-heading"></h3>
+      <p class="muted" id="adopt-intro"></p>
+      <div id="adopt-list" class="series-list"></div>
+      <div class="row">
+        <button type="button" id="adopt-cancel" class="secondary" data-i18n="common.cancel"></button>
+        <button type="button" id="adopt-submit" data-i18n="adopt.submit"></button>
+      </div>
+    </dialog>
+
     <div id="toast" hidden></div>
     <script src="/i18n.js"></script>
     <script src="/app.js"></script>
diff --git a/tests/test_import_flow.py b/tests/test_import_flow.py
index 74ba814..81296f5 100644
--- a/tests/test_import_flow.py
+++ b/tests/test_import_flow.py
@@ -1294,3 +1294,37 @@ def test_bulk_move_delete_and_count(client):
                           json={"ids": ids[1:]}).json() == {"deleted": 2}
     assert client.get("/api/requests/count?status=missing").json() == {"count": 1}
     assert [r["event"] for r in client.get("/api/history").json()] == ["deleted"] * 2
+
+
+def test_adopt_files_already_in_the_library(client):
+    root = client.tmp_path / "audio"
+    lib = client.post("/api/libraries", json={
+        "name": "Audio", "media_type": "audiobook", "root_path": str(root)}).json()["id"]
+    hobbit = client.post("/api/requests", json={
+        "library_id": lib, "title": "Der Hobbit", "authors": "Tolkien"}).json()["id"]
+    known = client.post("/api/requests", json={
+        "library_id": lib, "title": "Momo", "authors": "Ende"}).json()["id"]
+    for folder in ("Tolkien/Der Hobbit", "Ende/Momo"):
+        (root / folder).mkdir(parents=True)
+        for i in (1, 2):
+            (root / folder / f"{i:02d}.mp3").write_bytes(b"")
+    (root / "Tolkien" / "Notizen.epub").write_bytes(b"")  # other media type
+
+    # Momo already points at its folder, so only the Hobbit is offered
+    adopted = client.post(f"/api/import/library/{lib}", json={"items": [
+        {"path": str(root / "Ende/Momo"), "request_id": known}]}).json()
+    assert adopted == {"results": [{"path": str(root / "Ende/Momo"), "ok": True}]}
+    items = client.get(f"/api/import/library/{lib}").json()["items"]
+    assert [(i["name"], i["suggested_request_id"]) for i in items] == [("Der Hobbit", hobbit)]
+
+    resp = client.post(f"/api/import/library/{lib}", json={"items": [
+        {"path": items[0]["path"], "request_id": hobbit},
+        {"path": str(root / "Ende/Momo"), "request_id": known},  # no longer open
+        {"path": str(client.downloads), "request_id": hobbit},
+    ]}).json()["results"]
+    assert [r["ok"] for r in resp] == [True, False, False]
+    reqs = {r["id"]: r for r in client.get("/api/requests?status=imported").json()}
+    assert reqs[hobbit]["imported_path"] == str(root / "Tolkien/Der Hobbit")
+    assert (root / "Tolkien/Der Hobbit/01.mp3").exists()  # nothing moved
+    assert client.get(f"/api/import/library/{lib}").json()["items"] == []
+    assert [h["event"] for h in client.get("/api/history").json()] == ["adopted"] * 2
diff --git a/wordarr/api/imports.py b/wordarr/api/imports.py
index c8a7b74..d3abdde 100644
--- a/wordarr/api/imports.py
+++ b/wordarr/api/imports.py
@@ -6,8 +6,8 @@ from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from .. import config, connect
-from ..db import BookRequest, get_session, record
-from ..fsnames import decode_path, readable
+from ..db import BookRequest, Library, get_session, record
+from ..fsnames import decode_path, is_broken, readable
 from ..importer import matcher, mover, scanner
 
 router = APIRouter(prefix="/api/import", tags=["import"])
@@ -128,3 +128,84 @@ def do_import(data: ImportIn, background: BackgroundTasks,
         raise HTTPException(400, "nothing to import")
     connect.schedule(background, rows)
     return {"results": results}
+
+
+def _library(session: Session, library_id: int) -> Library:
+    lib = session.get(Library, library_id)
+    if not lib:
+        raise HTTPException(404, "library not found")
+    return lib
+
+
+def _open_for(session: Session, lib: Library) -> list[BookRequest]:
+    missing = session.scalars(select(BookRequest).where(
+        BookRequest.status == "missing", BookRequest.library_id == lib.id)).all()
+    return list(missing) + [r for r in _orphaned(session) if r.library_id == lib.id]
+
+
+@router.get("/library/{library_id}")
+def scan_library(library_id: int, session: Session = Depends(get_session)):
+    """Files already in the library that no request points at, matched against
+    the library's open requests, so an existing collection need not be imported
+    again."""
+    lib = _library(session, library_id)
+    imported = session.scalars(select(BookRequest.imported_path).where(
+        BookRequest.status == "imported", BookRequest.imported_path != "")).all()
+    covered = {Path(p) for p in imported}
+    # a folder holding an imported file, or a file inside an imported folder
+    above = {a for p in covered for a in p.parents}
+
+    def known(item: dict) -> bool:
+        p = Path(decode_path(item["path"]))
+        return p in covered or p in above or any(a in covered for a in p.parents)
+
+    items = [i for i in scanner.scan(Path(lib.root_path))
+             if i["media_type"] == lib.media_type and not known(i)]
+    open_reqs = _open_for(session, lib)
+    return {"root_path": lib.root_path,
+            "items": matcher.best_matches(items, open_reqs),
+            "requests": [{"id": r.id, "title": r.title, "authors": r.authors}
+                         for r in open_reqs]}
+
+
+class AdoptItem(BaseModel):
+    path: str
+    request_id: int
+
+
+class AdoptIn(BaseModel):
+    items: list[AdoptItem]
+
+
+@router.post("/library/{library_id}")
+def adopt(library_id: int, data: AdoptIn, background: BackgroundTasks,
+          session: Session = Depends(get_session)):
+    """Point open requests at files that are already in place. Nothing moves."""
+    lib = _library(session, library_id)
+    root = Path(lib.root_path).resolve()
+    open_ids = {r.id for r in _open_for(session, lib)}
+    results, rows = [], []
+    for item in data.items:
+        path = decode_path(item.path)
+        shown = readable(path)
+        req = session.get(BookRequest, item.request_id)
+        if is_broken(path):
+            error = "file name is not valid UTF-8, rename it first"
+        elif root not in Path(path).resolve().parents:
+            error = "path outside the library"
+        elif not Path(path).exists():
+            error = "path no longer exists"
+        elif not req or req.id not in open_ids:
+            error = f"request #{item.request_id} is not open in this library"
+        else:
+            error = ""
+        if error:
+            results.append({"path": shown, "ok": False, "error": error})
+            continue
+        req.status, req.imported_path = "imported", path
+        rows.append(record(session, "adopted", req, dest=path))
+        open_ids.discard(req.id)  # two files for one request: the first wins
+        results.append({"path": shown, "ok": True})
+    session.commit()
+    connect.schedule(background, rows)
+    return {"results": results}