Book Categories and Keywords: How Readers Find Your Book

Most readers find books in one of two ways. They browse a shelf, such as "Historical Mystery" or "Personal Growth", or they type something into a search box. Categories decide which shelves your book sits on; keywords influence which searches it appears in. Getting both right costs nothing and can make the difference between a book that's found and one that isn't.

How readers find books in a store

Choosing categories

Most stores use a hierarchy of categories, often based on the BISAC subject codes used across the book trade: a broad subject such as "Fiction" or "Self-Help", then narrower sub-genres beneath it. The narrower the category, the smaller the shelf, and the more likely your book is to be seen by readers who want exactly what you wrote.

1. Start with what the book is. Describe it in one line: "a cosy mystery set in a seaside bakery" or "a practical guide to Stoic habits for busy professionals".
2. Find the narrowest honest match. Look for sub-genres that match that line, not just the broad subject.
3. Check what's already there. Browse the category and see whether your book would look at home beside the books in it.
4. Use every slot wisely. Cover different angles of the book, such as genre, setting and theme, rather than three near-identical categories.
5. Stay accurate. A romance listed under thrillers disappoints readers and earns poor reviews.

Categories when your book crosses genres

Plenty of books sit between genres: a romance with a mystery at its heart, a memoir that doubles as a business book, a fantasy with strong horror elements. This is where multiple category slots earn their keep. Use your first choice for the genre readers would say the book belongs to if they had to pick one, and further slots for the secondary genres, so readers of each can find it.

Be careful not to let the secondary genre take over. If the mystery is a small thread in a romance, a mystery reader who picks it up expecting a puzzle may leave a disappointed review. Ask yourself which readers will love the book most, and make sure those readers are the ones most likely to find it.

Writing keywords that work

Keywords are the phrases a reader might type when looking for a book like yours. KDP's own advice is to think like a reader and suggests types of keywords that help: setting, character types, character roles, plot themes and story tone.

Phrases of two or three words often work better than single words, because they match how people search. "Book" or "novel" on their own do nothing; "cosy bakery mystery" can.

What to avoid in keywords

KDP publishes a list of things not to include, and the same principles make sense everywhere:

• Repeating your title, author name or categories. These are already searchable.
• Quality claims such as "best novel ever".
• Time-sensitive words such as "new", "on sale" or "available now".
• Generic words such as "book".
• Other authors' names or brands without permission. They misrepresent your book.
• Program names such as "Kindle Unlimited" or "KDP Select".
• Misspellings and punctuation variants. Stores usually handle these already.

Two worked examples

A novel

Imagine a mystery about a retired schoolteacher who solves crimes in a small Cornish fishing village, with no violence on the page and plenty of tea. The broad category is Fiction, then Mystery. The precise shelves are cosy mystery and, if the store has one, amateur sleuth. A third angle might be a setting-based category, such as British or small-town fiction, if one exists.

The keywords then fill the gaps the categories leave: "cozy mystery Cornwall", "retired teacher sleuth", "clean village mystery", "British seaside whodunit", "tea shop murder mystery". Each is a phrase a reader of this kind of book might genuinely type, and none repeats the title or the author name.

A non-fiction book

Now imagine a practical book about building better daily habits for parents with young children. The broad category is Self-Help, then Personal Growth. Narrower angles could be time management and parenting, so the book appears on shelves for both interests.

Keywords here focus on the reader and the problem: "habits for busy parents", "morning routine with kids", "time management for mums and dads", "small daily changes", "stop feeling overwhelmed". The subtitle does its share too: "Simple Habits for Parents Who Never Have Enough Time" is searchable, readable and tells a browsing reader exactly who the book is for.

Your description helps search too

Many stores search book descriptions as well as keywords, and BooksOasis does. That doesn't mean stuffing the description with phrases. It means describing the book naturally in the words readers use: if your book is a cosy mystery set in Cornwall, say so in the first lines. A description written for readers usually contains the right words already. See writing a book description for how to write one that sells.

Categories and keywords on KDP

On KDP, you choose up to three categories when you set up a book, and up to seven keywords or short phrases. KDP recommends testing your keywords by searching Amazon before you publish, and keeping keywords consistent across a book's formats. For a full look at KDP's options, see KDP alternatives and the platform's own help pages.

Genres and keywords on BooksOasis

Because titles, subtitles, pen names, series and descriptions are already searched, your keywords can focus on the words readers use that don't appear anywhere else on the listing. A book needs at least 3 genres and 3 keywords before it can go to review, and a live book can't be edited below that. Changes to genres and keywords on a live book are checked like other listing edits.

The subtitle: a keyword you can see

A subtitle is searched and displayed, which makes it one of your most valuable pieces of text. For non-fiction, it should say plainly what the book does: "How to Learn Faster, Think Clearer, and Act with Purpose". For fiction, a series name and number or a genre hint can help: "A Seaside Bakery Mystery". Keep it honest and readable; a subtitle stuffed with keywords looks spammy and puts readers off.

Researching what readers search

• Start typing in a store's search box and note the suggestions that appear; they reflect common searches.
• Read comparable books' listings to see how they describe themselves, without copying.
• Read reviews of similar books. Readers describe what they loved in their own words, which are often the words they search with.
• Ask your readers how they'd describe the book to a friend.

Categories and keywords for a series

Keep a series consistent: the same core genres across every book, and keywords that describe the series as a whole plus anything specific to each book. Readers who browse a shelf and find book three should be able to find book one easily, so make sure every book is linked to the series. See publishing a book series.

Reviewing after launch

Categories and keywords aren't set-and-forget. A few weeks after launch, search for your keywords and see whether your book appears and what sits beside it. If a keyword brings up books very different from yours, replace it. If readers describe the book in reviews using words you hadn't thought of, try them. Small, occasional adjustments often work better than constant changes, because they give you time to see what each change actually did.

Common mistakes

Sources

Checked October 2026: KDP: make your book more discoverable with keywords; KDP categories; BooksOasis listing rules.

In short

Pick the most precise honest genres, fill keyword slots with reader-style phrases that aren't already on your listing, make your subtitle work, and review everything a few weeks after launch. It's free, it takes an afternoon, and it helps the right readers find your book.

Curious how readers find books? Browse our reading guides on the BooksOasis store.