diff --git a/docs-developers/server/api/reference.md b/docs-developers/server/api/reference.md
index 082319c..5a30a15 100644
--- a/docs-developers/server/api/reference.md
+++ b/docs-developers/server/api/reference.md
@@ -3322,7 +3322,7 @@ what the first does).
 | `min_duration` · `max_duration` | number (seconds) | - | inclusive bounds; `0` means no bound |
 | `added_after` | date | - | inclusive lower bound on `added_at`: `YYYY-MM-DD` (used as is) or an RFC 3339 time (any offset; converted to UTC before comparing) |
 | `added_before` | date | - | exclusive upper bound, same formats |
-| `issue` | string | - | one [Health issue](#get-apiv1adminissues) kind's books: `scan_error`, `suspect`, `split_discs` (one row per split book: its first disc), `no_cover`, `unmatched`, `no_chapters`, `detailed_chapters` or `transcode` (not `duplicate`, which comes as groups from [`/admin/issues/duplicates`](#get-apiv1adminissuesduplicates)). Books an admin ignored for that kind are left out. Any other value is `400 unknown issue` |
+| `issue` | string | - | one [Health issue](#get-apiv1adminissues) kind's books: `scan_error`, `suspect`, `split_discs` (one row per split book: its first disc), `no_cover`, `unmatched`, `series_spellings`, `no_chapters`, `detailed_chapters` or `transcode` (not `duplicate`, which comes as groups from [`/admin/issues/duplicates`](#get-apiv1adminissuesduplicates)). Books an admin ignored for that kind are left out. Any other value is `400 unknown issue` |
 | `issue_ignored` | `true`\|`false` | - | with `issue`, list **only** the books an admin ignored for it; without `issue` it is `400 issue_ignored needs an issue` |
 | `sort` | string | `title` | `title` \| `author` \| `surname` \| `series` \| `narrator` \| `published` \| `added` \| `duration` \| `size` |
 | `order` | string | `asc` | `asc` \| `desc` |
@@ -4468,7 +4468,13 @@ a scan last finished.
 
 - `categories` - one entry per kind, always in this order: `scan_error`,
   `suspect`, `split_discs`, `duplicate`, `no_cover`, `unmatched`,
-  `no_chapters`, `detailed_chapters`, `transcode`. `detailed_chapters` is a
+  `series_spellings`, `no_chapters`, `detailed_chapters`, `transcode`.
+  `series_spellings` is a book whose main series another book of its library
+  spells another way (the same series in a different case, accent, punctuation or
+  spacing; see [`/series`](#get-apiv1librariesidseries)); every book of such a
+  series is counted, and
+  [`/admin/issues/series-spellings`](#get-apiv1adminissuesseries-spellings) lists
+  them per series. `detailed_chapters` is a
   book whose last [community chapter check](../community-chapters.md) found
   finer community chapters that fit (`refine`) and whose chapter source no
   admin has chosen; the console's fix is a bulk edit with
@@ -4534,6 +4540,51 @@ different libraries are deliberate and never grouped).
 - At most 500 groups (counted after that filter, so every ignored group can be
   reached), ordered by library and the kept copy's path.
 
+### `GET /api/v1/admin/issues/series-spellings`
+
+The series a library's books spell more than one way, one entry per series and
+library, from the same rule as the `series_spellings` count.
+
+| Query param | Type | Notes |
+|---|---|---|
+| `library_id` | int | one library; a non-positive or non-integer id is `400 invalid library_id` |
+| `ignored` | `true` | return the series with a book an admin ignored for `series_spellings` (instead of those with a book not ignored) |
+
+```json
+{
+  "groups": [
+    {
+      "library_id": 5,
+      "suggested": "He Who Fights with Monsters",
+      "spellings": [
+        { "name": "He Who Fights With Monsters", "books": 8 },
+        { "name": "He Who Fights with Monsters", "books": 5 }
+      ],
+      "books": 13
+    }
+  ]
+}
+```
+
+- `suggested` - the spelling to offer, by the rule
+  [`/series`](#get-apiv1librariesidseries) names a series by (the spelling its
+  matched books use most, else the one most of its books use, ties alphabetical),
+  counted over this library's books whose main series it is. So it can differ from
+  the name `/series` or [`/admin/series`](#get-apiv1adminseries) gives when other
+  libraries or other-series lists spell it too. The console offers it first.
+- `spellings` - every spelling the library's books give it as their main series,
+  with its books, most books first (ties alphabetical). Ignored books' spellings
+  are listed too, so a rename leaves none behind.
+- `books` - all of the books in that library whose main series it is (a book that
+  lists it only among its other series is not counted, and a rename doesn't touch
+  it).
+- A series can be in both views while some of its books are ignored and some not.
+  At most 200 entries, ordered by `suggested` (case-insensitive), then library.
+
+The console's fix is a [bulk edit](#post-apiv1adminbooksbulk) setting `series` on
+the books of the other spellings, as an author merge is; ignoring a series is a
+`series_spellings` ignore of every one of its books.
+
 ### `POST /api/v1/admin/issues/ignore` · `DELETE /api/v1/admin/issues/ignore`
 
 `POST` stops listing books under one issue kind; `DELETE` lists them again (the
@@ -4544,7 +4595,7 @@ console's Undo and "Show again"). For duplicates, ignore every copy of a group
 { "kind": "no_cover", "books": [ { "library_id": 1, "path": "Sun Tzu/The Art of War" } ] }
 ```
 
-- `kind` - one of the nine kinds above.
+- `kind` - one of the ten kinds above.
 - `books` - 1 to 1000 `{library_id, path}` refs. The books needn't be indexed:
   the rows are path-keyed durable state (`issue_ignores`), so an ignore
   survives rescans and rebuilds and moves with the book. A ref in a library
diff --git a/docs-developers/server/data-model.md b/docs-developers/server/data-model.md
index 6ab719c..70ef8ef 100644
--- a/docs-developers/server/data-model.md
+++ b/docs-developers/server/data-model.md
@@ -4,7 +4,7 @@ description: "The SQLite schema behind audiosilo-server: the rebuildable index v
 ---
 
 The schema lives in `internal/store/migrations/` as numbered SQL files
-(`0001_init.sql` … `0040_server_state.sql`), embedded into the binary and
+(`0001_init.sql` … `0041_series_key.sql`), embedded into the binary and
 applied by `store.Open` at startup. This page documents the **resulting current
 schema**, noting which migration added what.
 
@@ -13,7 +13,8 @@ schema**, noting which migration added what.
 The schema is deliberately split in two, and the split is the most important
 thing to understand before touching it:
 
-- The **rebuildable index** - `books`, `book_files`, `chapters`, `books_fts` -
+- The **rebuildable index** - `books`, `book_files`, `chapters`,
+  `book_more_series`, `books_fts` -
   is a cache of what the scanner found on disk. It can be dropped and rebuilt
   from a rescan at any time. `books.id` is an internal artifact of this half:
   it must **never** appear in the API contract or in durable user state.
@@ -76,6 +77,7 @@ erDiagram
     libraries ||--o{ books : "rebuildable index"
     books ||--o{ book_files : ""
     books ||--o{ chapters : ""
+    books ||--o{ book_more_series : "ON DELETE CASCADE"
     books ||--|| books_fts : "rowid = books.id"
     libraries ||--o{ progress : "path-keyed, NO FK to books"
     libraries ||--o{ bookmarks : ""
@@ -203,7 +205,7 @@ covered in [Auth & security](auth-and-security.md#authorization-shares--scope).
 `scan_error_file`, `scan_error_detail` and `suspect_parts` in 0017; `split_parent` in
 0022; `cover_art` and `cover_color` in 0023; `chapters_source`, `chapters_fit`,
 `scanned_chapters` and `chapters_hash` in 0035; `released` and `released_checked`
-in 0037)* - one row per book,
+in 0037; `series_key` in 0041)* - one row per book,
 `UNIQUE (library_id, rel_path)`. Columns: `is_folder` (folder book vs
 single-file book), identity metadata (`title`, `author`, `series`,
 `series_index`, `narrator`), `duration`, `asin`/`isbn` (optional external ids -
@@ -217,7 +219,14 @@ that sets or reverts `series` to one of these swaps the two, writing the list
 and `series_index` as overrides (a value the scan already gives is reverted to
 it instead; the console sends the values itself, so its swap writes them as
 edits);
-the full-text index's series column holds every series name), `released` (the date the file's tags give, `YYYY[-MM[-DD]]` via
+the full-text index's series column holds every series name), `series_key` (the
+main series' key, `catalog.seriesKey`: `match.SeriesKey`, so case, accents,
+punctuation and spacing aside, or the name itself when it has no letter or digit;
+`''` for no series), written by Go in `refreshEffective` beside `series` and never
+computed in SQL, so every spelling of a series is found by one index seek
+(`idx_books_series_key` on `(library_id, series_key, series, series_index)`, which
+replaced 0001's `idx_books_series`; `series` sits before `series_index` so a series'
+spellings are adjacent for Health's `series_spellings`), `released` (the date the file's tags give, `YYYY[-MM[-DD]]` via
 `metadata.ReleaseDate`: usually the recording's, so it is a separate scanned
 column, never `published`, read only by the admin list's release-date sort as
 the fallback for a book with no `published`) and `released_checked` (`1` once a
@@ -359,6 +368,15 @@ admin state like `book_overrides`, kept apart from it because it is not a
 metadata value (no part of `edited` / `edited_fields`); moved with the book's
 other edits, never copied onto a joined book.
 
+**`book_more_series`** *(0041)* - a book's other series by key: one row per
+series in `more_series` that isn't its main one (`book_id` → `books` `ON DELETE
+CASCADE`, `library_id`, `series_key`, `position`; primary key `(book_id,
+series_key)`, `WITHOUT ROWID`, index `(series_key, library_id, position)`).
+Rewritten from the effective values by `refreshEffective` (`keyOtherSeries`), as
+`books.series_key` is, so a series filter with memberships, the series order and
+the next book find a book through its list by an index seek, and the rails'
+`SeriesBooks` without reading every list.
+
 **`books_fts`** *(0001)* - see [FTS design](#fts-design-books_fts) below.
 
 ### Durable per-user state (path-keyed, no FK to books)
@@ -743,11 +761,23 @@ every other table. `catalog/server_state.go` reads and writes a key
 `putServerState`), taking a querier or execer so a caller can read and write one
 key in a single transaction.
 
-One key so far, `support_card`: the answer to the admin console's
-[support card](web-ui.md#the-support-card), `{"choice":"donated"}` or
-`{"choice":"snoozed","until":"<time>"}`. `catalog.SetSupportChoice` reads and
-writes it in one transaction, so a donation is never downgraded by a later
-snooze.
+Its keys:
+
+- `support_card`: the answer to the admin console's
+  [support card](web-ui.md#the-support-card), `{"choice":"donated"}` or
+  `{"choice":"snoozed","until":"<time>"}`. `catalog.SetSupportChoice` reads and
+  writes it in one transaction, so a donation is never downgraded by a later
+  snooze.
+- `title_positions`: `true` once `catalog.PlaceByTitles` has given the books
+  indexed before the title rule their series position from their title.
+- `series_keys`: the version the stored series keys were computed with
+  (`seriesKeysVersion`: the key rules' number, then Go's Unicode version and
+  the Unicode version of x/text's normalization tables). `catalog.KeySeries` keys
+  every book at start while it is missing or different (first for the books
+  indexed before 0041, then after an upgrade that reads a name another way),
+  before the listener; a failure stops the start, as a failed migration does, since
+  every series filter reads only the keys (see `books.series_key` and
+  `book_more_series` in [The rebuildable index](#the-rebuildable-index)).
 
 ### Community metadata cache
 
@@ -844,8 +874,9 @@ A `books` row always holds the **effective** metadata, built in layers:
 
 `bookLayers.resolve` (in `internal/catalog/overrides.go`) is the single
 statement of that precedence, and of each field's source. `refreshEffective`
-writes its values into the book's metadata columns and chapter titles and
-refreshes the book's `books_fts` row from the result; the admin book page shows
+writes its values into the book's metadata columns (with `series_key`, and the
+book's `book_more_series` rows) and chapter titles and refreshes the book's
+`books_fts` row from the result; the admin book page shows
 the same resolution as provenance, so the two can't disagree. Every write path calls
 it inside its own transaction - `UpsertBook` (each scan or on-demand index),
 `SetEnrichment`, and `EditBook`/`EditBooks` (the admin edits, the bulk form
@@ -946,6 +977,7 @@ The migration history so far:
 | 0038 | `more_series` | `books.more_series` (`TEXT NOT NULL DEFAULT '[]'`), the effective list of a book's other series |
 | 0039 | `more_series_index` | the partial index `idx_books_more_series` on `books(library_id) WHERE more_series <> '[]'`, so the reads of the books in more than one series (a series' members, `/series` with `memberships=1`) skip the rest |
 | 0040 | `server_state` | `server_state` (`key`, `value`, `updated_at`), small server-wide facts that aren't settings; the first key is the support card's answer: see [Server state](#server-state) |
+| 0041 | `series_key` | `books.series_key` and `book_more_series`, a series stored by its key so every series filter is an index seek in any spelling; `idx_books_series_key` replaces `idx_books_series`, and `idx_books_more_series` (0039) goes, since nothing reads it any more. Rows indexed before it are keyed at start by `catalog.KeySeries` (server_state `series_keys`), which also puts every stored `more_series` list through the list rules first |
 
 ## SQLite choices
 
diff --git a/docs-developers/server/scanner.md b/docs-developers/server/scanner.md
index 88461f5..040e448 100644
--- a/docs-developers/server/scanner.md
+++ b/docs-developers/server/scanner.md
@@ -628,6 +628,7 @@ predicate over `books b`, shared by the counts (`IssueCounts`) and the lists
 | `split_discs` | it is the **first** disc (by `rel_path`) of a book split across disc folders: `split_parent` is set and that folder has no override of either mode (one settles how it reads). Its fix sets `book` on `split_parent`, which joins the discs |
 | `no_cover` | a scan has checked it (`has_cover` not `NULL`) and it has no sidecar image, no embedded art and no custom cover |
 | `unmatched` | it has no ASIN and no ISBN. Only offered while community metadata is on |
+| `series_spellings` | another book of its library spells its main series another way: the same `series_key`, a different `series` (two range seeks on `idx_books_series_key`, a spelling below its own or above). `SeriesSpellingGroups` lists them per series from the same predicate; the console's fix sets one spelling with a bulk edit |
 | `no_chapters` | it is longer than **2 hours** and has at most one chapter. The console shows why community chapters weren't used from the row's `chapters_check` (a failed [community chapter check](community-chapters.md)) |
 | `detailed_chapters` | its last community chapter check is `refine` (the community's finer chapters fit) and it has no `chapter_source` choice; picking either source settles it |
 | `transcode` | its codec doesn't play in browsers (`media.DirectPlayable`) |
diff --git a/docs-developers/server/web-ui.md b/docs-developers/server/web-ui.md
index 663cace..028876e 100644
--- a/docs-developers/server/web-ui.md
+++ b/docs-developers/server/web-ui.md
@@ -502,7 +502,12 @@ CSP-sensitive work against a real build served by Go. The console's own gate is
   ignored books (`?issue_ignored=true`). Duplicates
   (`duplicates.tsx`) render each group side by side from
   `GET /admin/issues/duplicates`, the copy worth keeping first, with "They're
-  different books" (ignore every copy). The category and the ignored view live
+  different books" (ignore every copy). Series spelled several ways
+  (`series-spellings.tsx`) is grouped too: one notice per series and library from
+  `GET /admin/issues/series-spellings`, the suggested spelling picked first in a
+  select, "Use this spelling" running the Authors page's merge (`useMerge` on `series`:
+  a bulk `series` edit of the books whose main series is that series, with Undo),
+  and Ignore / Show again covering every one of the series' books. The category and the ignored view live
   in the URL (`?issue=<kind>&ignored=1`). Without `?issue=` the page opens the
   first category needing attention and keeps it open, so clearing it shows "All
   clear" instead of jumping to the next. "Check again" queues a scan of every
diff --git a/docs-users/admin/books.md b/docs-users/admin/books.md
index 6079f92..bb4bf02 100644
--- a/docs-users/admin/books.md
+++ b/docs-users/admin/books.md
@@ -426,6 +426,12 @@ one person. Use the library filter and **Filter authors** (or **Filter
 narrators**) to narrow the list. Click a name to open **Books** filtered to that
 person, their shared books included.
 
+The page shows 120 people at a time. Use the page numbers under the tiles to
+move through a long list. The page and the filter are part of the page's
+address, so after you open a name, **Back** returns you to the same page and the
+same filter. A new filter, or picking another library, starts again on the first
+page.
+
 ![Library > Authors](/img/screenshots/admin/authors.png)
 
 ### Merging two spellings
@@ -465,7 +471,9 @@ Monsters") are one series, everywhere: on this page, in the books list
 filtered to the series and in the players. The card is named the way your
 matched books spell it, or else the way most of its books do. Names that
 differ in any other way stay apart ("The Expanse" and "Expanse" are two
-series), so fix those with a [bulk edit](#changing-many-books-at-once).
+series), so fix those with a [bulk edit](#changing-many-books-at-once). To make
+every book of a series spell it the same way, use
+[Series spelled several ways](health.md#series-spelled-several-ways) in Health.
 
 A book with a series but no series number takes the number its title gives
 when the title is the series' name followed by a number: "He Who Fights with
diff --git a/docs-users/admin/health.md b/docs-users/admin/health.md
index ba6e2af..988b8ca 100644
--- a/docs-users/admin/health.md
+++ b/docs-users/admin/health.md
@@ -48,6 +48,7 @@ below.
 | **Likely duplicates** | Copies of one book in the same library. See [Duplicates](#duplicates). | A side-by-side comparison. |
 | **Missing covers** | No cover image in the book's folder and none inside its files. | **Upload a cover** opens the book's page, where **Change cover** adds one (see [Covers](books.md#covers)). |
 | **Not matched to community metadata** | The book has no ASIN or ISBN, so community metadata can't find it. Only shown while [community metadata](server.md#community-metadata) is on. | **Review match** opens the book's page with the match dialog open (see [Matching](books.md#matching-with-community-metadata)). To match the whole list at once, use **Match automatically** above it (see [Matching every book at once](#matching-every-book-at-once)). |
+| **Series spelled several ways** | Books of one series that spell its name differently, for example "He Who Fights With Monsters" on some books and "He Who Fights with Monsters" on others. AudioSilo already shows them as one series; this is only about every book saying the same. See [Series spelled several ways](#series-spelled-several-ways). | **Use this spelling** sets one spelling on every book of the series. |
 | **Long books without chapters** | Books over two hours long with no chapter marks (or a single chapter). Listeners can play them but can't jump between chapters. When the book was checked against the community's chapter lists and they couldn't be used, a second line says why, for example "Community chapters: for another edition" or "Community chapters: cross from one file into the next. Merging the files would let them fit" (see [Community chapters](books.md#community-chapters)). | None in the console. [Match](books.md#matching-with-community-metadata) the book so its community chapters can be used (a book with no chapters of its own gets them automatically once they fit), add chapters to the file with your tagging tool, or ignore it. |
 | **More detailed chapters available** | The book has chapters, and the community has finer ones that fit this copy ("Has 34 chapters; the community's finer ones fit this copy"). Nothing changes until you use them. | **Use detailed chapters** switches the book to the community's chapters. Using them on the book's page does the same. Once you have chosen, the book stays off this list, even if you later switch it back to the file's chapters. |
 | **Converted to play in browsers** | The audio format doesn't play in web browsers, so the server converts it while someone listens in the web player. The apps play it as it is. | None needed: it works. Re-encode the file if you'd rather the server didn't convert it, or ignore it. |
@@ -197,6 +198,33 @@ when it was **Added**. **Open book** opens a copy's page.
   the library folder and rescan; listening progress on the deleted copy's path
   is kept (see [Jobs](#what-a-removed-book-leaves-behind)).
 
+### Series spelled several ways
+
+AudioSilo treats names that differ only in capitals, accents, punctuation or
+spacing as one series, so the Series page already shows one card for them. The
+books themselves still say it differently, which shows in the players' book
+details, the Books list and the library export. This list sorts that out.
+
+Each series has its own notice, for example "“He Who Fights With Monsters”
+looks like He Who Fights with Monsters", with how many books carry the other
+spellings.
+
+- The spelling it offers is the one this library's matched books use most, else
+  the one most of its books use (the rule the Series page names a series by, so
+  the two usually agree; the Series page can pick another when it shows every
+  library, or when a book lists the series among its other series). Pick another
+  from the list beside the button if you prefer it.
+- **Use this spelling** sets that spelling on every book that spells the series
+  another way, as an edit on each book; the files are untouched. Each book keeps
+  its number in the series. The toast has an **Undo** button, and you can also
+  revert the series on any single book's page. It works like
+  [merging two spellings of an author](books.md#merging-two-spellings).
+- **Ignore** stops suggesting the series, for all its books. **Show ignored**
+  lists those series, each with **Show again**.
+
+Only books in the same library are compared. AudioSilo never changes a spelling
+on its own.
+
 ### When a library is offline
 
 If a library's folder can't be read (typically a network share that
diff --git a/static/img/screenshots/admin/authors.png b/static/img/screenshots/admin/authors.png
index 8c0b124..cc9f65b 100644
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diff --git a/static/img/screenshots/admin/health-issues.png b/static/img/screenshots/admin/health-issues.png
index 2ffc816..466057e 100644
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