9th October, 2026
7 min read
What is a Book Category? Book Categories For Authors Explained
Written by:
Jonathan White
What is a Book Category?
A book’s category is a classification system that organises books by shared themes, reader expectations and market positioning. It helps tell booksellers, retailers and readers what type of book you have written and where it should be positioned. It is one of the essential parts of its ‘Metadata’, or ‘Bibliographic Information’ as it used to be referred to. It is one of the many pieces of information that needs to be filled in for each newly published book to help retailers, as well as customers, locate the book amongst the vast number of new titles which are appearing each month in the book trade.
As an author you might have thought that giving your book a subject category was one of the easier pieces of description you needed to attach to your book. Unfortunately, in this digital age, nothing is ever as easy as it was when all you were doing was saying in which part of a bookshop you might actually find your book!
The main problem today is that there are a number of different book categorisation systems which different book retailers use and, probably more importantly, you can now add different levels of specification to the category you can give to a book depending on how you are publishing it. As a part of our Trade Marketing Service, book classification is something that we look at everyday. For self-published authors, however, it can be something that’s quite daunting. So, in this article we will look at what book classification is, bust some common classification myths, explore why it is so important to get the category for your book right, and answer some common questions authors have about book classification.
What Are The Different Book Categorisation Schemes?
There is not just one book categorisation scheme for books used by everyone, but rather three main ones which are used by different retailers and in different parts of the world. These are BIC, BISAC and Thema.
- BIC is the original book categorisation scheme used in the UK
- BISAC is the one that was used in the USA
- THEMA is the newest, but becoming the most important
At some point, THEMA may well be the only one that is used by retailers: but until then, books need to be categorised under all these schemes.
Whilst there are others, the three main schemes are the ones every book needs to be categorised in when you are setting up a new book, so that the information can be transmitted out to all book retailers.
How Should I Use The Different Book Categorisation Schemes?
Authors should make sure that their books use the same subject headings across all book categorisation schemes.
As there are three schemes, some authors think that this gives you an ideal opportunity to categorise a book which might well come under several different subject headings. So if you have written a spy story, set in the 1890’s and revolving around trying to sink one of the great liners of the day you might think this would give you an ideal opportunity to categorise a book under historical fiction in one scheme, thriller in another and books on ships in another. This though is actually the worst thing you can do, as each of these book categorisation schemes is used in different parts of the world and by different retailers, so actually you are just causing confusion by giving it a different category in each scheme.
The categorisation of the book really needs to be as closely aligned as possible across the three schemes to avoid any confusion about where a title can be found. Again though this is not quite as easy as it may sound, as the same category quite often does not actually exist across all three schemes so sometimes you just have to choose the categories that most closely align across all three.
Can You Categorise Your Books In Multiple Subject Categories?
In most places, you can only categorise your book in one subject category. As Amazon always likes to be a bit different, they give you an opportunity to give your book multiple subject categories. It’s very important that you only do this if you publish your book directly with Amazon. For any other publisher supplying their book to Amazon, like we do, you should only give each book a single subject category.
Authors should be aware that Amazon might then use their own algorithms to generate other categories where they believe the book could be placed within the Amazon book catalogue, but for anyone publishing a book externally to Amazon and wishing to sell it through them, it is just one category we give to each book.
As Amazon is by far and away the biggest and most important retailer of books around the world, you do really want to get the category of the book right here.
Why Does Amazon Allow You To Choose Multiple Book Categories?
Amazon gives you the opportunity to give your book multiple categories as a way of encouraging authors to publish directly with them. The downside of this, of course, is if you do publish your book directly with Amazon you are not going to be able to sell it anywhere else away from the Amazon website.
Does Your Book Category Change Across Different Formats?
The answer is across most retailers, no. You only have one book category, and that works across all formats. Where it gets confusing is when you look at different formats on Amazon.
As we said, Troubador-supplied paperbacks will only have one category on Amazon. However, to get an ebook sold on Amazon, they have to be uploaded directly on Amazon’s publishing portal, rather than just being supplied by a publisher. This means that, technically speaking, your ebook could have multiple categories (as it’s published on Amazon), whereas your paperback cannot (as it’s supplied by an external publisher).
What’s The Difference Between Book Categorisation and Book Rankings on Amazon?
Book categorisation is not the same as book rankings. However, the ranking is informed by but not directly linked to your book categorisation. This means you might find your book is being ranked in a subject category that you do not think your book has been categorised under. This is because the ranking of your book is completely determined again by Amazon’s own internal algorithms. Not all categories might have rankings attached to them, and Amazon’s ranking system is very much more complicated than just being tied to the book’s category.
Can AI Choose My Book Category For Me?
Whilst people think that AI might be able to categorise their book for them, AI tools will often provide incorrect categories. This is because AI will give you the answer as if you are only publishing your book with Amazon, so does not address what you can and cannot do if you are publishing your book elsewhere.
Which means that we’ll often have authors ask us to give a book multiple subject categories. However, this is not possible for a physical version of the book when we are supplying to Amazon as an external publisher, rather than publishing directly on Amazon.
As a result of this, we recommend that authors do not use AI to provide book classifications.
Can I Add Additional Information To My Book Categorisation?
Although you can only give each book one main category in each scheme, it is possible to give your book additional information. This information could include a country that a book is set in, a time period, and the age range it's aimed towards.
We recommend that you give all the additional information that you can attach to your main book category.
How Do I Choose The Right Book Category?
These are the recommended steps to help you find the right book category:
- Identify your book's primary genre/topic
- Identify your target reader
- Choose the closest category in BIC
- Find the closest equivalent in BISAC
- Find the closest equivalent in Thema
- Add relevant additional information, such as location, period or age range
- Get professional advice if the category is unclear.
It can be difficult if you feel your book fits into multiple categories (i.e, if it’s historical and a crime book), but you do need to decide which one fits best. If you’re concerned, you may want to seek professional guidance, as book categorisation is very important, and not something you want to get wrong.
Summary
Book categorisation is a crucial part of your book’s metadata, which helps communicate to retailers whereabouts your book will sit on their shop floor. This can be a confusing and overwhelming part of the self-publishing process, which is exactly why we’re here to help.
As a part of our book setup and Trade Marketing services, we set up all of our authors’ metadata, to ensure that retailers have accurate information on your titles, and help build your book’s chances of success.
To learn more about the importance of metadata, check out our article here.
About the Author
Jonathan White
Sales and Marketing Manager
Before joining Troubador in 2017, Jonathan worked for more than 30 years in many different areas of the book industry. Starting in book retailing, where he was a book buyer and bookshop manager for some of the largest London bookshops, he then moved over to publishing, where he has worked for big-name publishers such as Oxford University Press, Chrysalis Books, Anova Books and Phaidon. He has worked in the UK book trade, spent time in International sales, and lived overseas for several years while continuing to work in publishing.
