Book Genres Explained: A Guide for Authors

Many authors start a book without thinking about genre, and that is fine while you draft. But once the manuscript reaches an agent, a publisher or an online store, the question becomes unavoidable: where does this book sit on the shelf? If you can answer it clearly, you make it easier for everyone to put the book in front of the right readers.

This guide covers the major fiction genres, clears up some common confusions and shows where classification matters in practice.

What a genre is, and what it isn’t

A genre groups books that raise similar expectations: about the kind of tension, the setting, the ending. A romance promises that the relationship is central and ends well. A mystery promises a crime and its solution. Genres are less like boxes and more like agreements between a book and its readers.

The main fiction genres

The borders are porous, and many successful books blend genres. Romantasy, for instance, pairs fantasy with a love story that carries as much weight as the world and its conflict. For the precise line between two of the biggest genres, see Mystery vs. Thriller.

Subgenres: where readers actually browse

The main genre tells a reader which part of the store to head for. Most readers search more narrowly than that. A cozy mystery fan does not automatically pick up a gritty procedural, and a space opera reader is not necessarily looking for dystopia. Subgenres bundle very specific expectations about tone, darkness, pace and ending.

For you, that means knowing your subgenre and its conventions. You do not have to meet every one, but you should know which you are breaking and why. A useful exercise is to name two or three recent titles your book could sit beside. Agents ask for exactly these comparable titles, or comps, in a query letter.

Why classification matters

Genre is not a formality. At several points it decides whether your book is found at all:

• Agents and publishers: agents represent particular genres and imprints publish specific lists. A query that does not name its genre clearly may reach the wrong person or no one. See How to Write a Synopsis for the documents that go with it.
• Retail and libraries: in the US, books are classified with BISAC subject codes maintained by the Book Industry Study Group; in the UK and internationally, the Thema scheme is increasingly used. These codes decide where a book is shelved and how it appears in catalogues.
• Online stores: Amazon, Apple Books, Kobo and others sort books into categories and subcategories. As a self-published author you choose these categories and keywords yourself. Too broad a category makes a book invisible; the wrong one earns disappointed reviews.
• Cover and blurb: readers recognise a genre in seconds from colour, type and imagery. A cover that signals a different genre from the content attracts the wrong audience.

Common classification mistakes

• Trying to be everything. “A fantasy romantic thriller with mystery elements for all ages” sounds generous but tells no one where the book belongs. Name one primary genre and at most one defining blend.
• Confusing age category with genre. Calling a book YA does not yet say what kind of story it tells.
• Classifying by setting alone. A novel set in medieval England is not automatically historical fiction if the love story or the crime is what really drives it.
• Hiding from the label. Some authors call a genre novel literary because it feels safer. It helps no one: the right readers cannot find it, and the wrong ones put it down disappointed.
• Picking categories for low competition. A small, ill-fitting store category may bring a quick bestseller badge, but it also brings readers with the wrong expectations.

Blends and new labels

Genres evolve. New labels tend to appear where readers keep searching for a particular mix, such as romantasy, cozy fantasy or climate fiction. Some of these labels settle into retail categories; others remain keywords in online stores and on social media. It pays to know them, because in your blurb and keywords they reach readers a main genre alone would miss. The formal classification, though, is still your primary genre.

Finding your own book’s genre

If you are unsure, do not start with setting or characters. Start with the core: what is the central question of your book, and how should the reader feel at the end? If the love story is central, it is a romance, even if there is a murder. If the murder is central, it is a mystery, even if two characters fall in love.

Frequently asked questions

How many book genres are there?

There is no fixed number. Most overviews list eight to twelve main fiction genres, with dozens of subgenres beneath them and new blends appearing all the time.

Is young adult a genre?

No. Young adult is an age category, aimed mainly at teenage readers. Within it you find every genre, from fantasy to thriller.

Can my book belong to more than one genre?

Yes, many books blend genres. For agents, retailers and online stores you should still name one primary genre, so it is clear where the book will be looked for first.