Subject codes are coded categorizations that are standard throughout the publishing industry and are essentially genre codes. The codes help librarians, bookstore owners, and online retailers, like Amazon, categorize books and decide where to "shelve" them and how to merchandise them based on topic. Subject codes help signal to potential buyers, retailers, distributors, and search engines what your book is about—the primary genre(s), topic(s), and theme(s) that matter in regard to your book. Without these codes, readers and those within the industry cannot identify what your book is about or if they'd like to stock or read it.
The book industry has two standardized subject code classification systems: BISAC and Thema. BISAC codes are used primarily for the U.S. market while Thema codes are used for all international markets outside the U.S. For the best discoverability, it's recommended to use both BISAC and Thema subject codes.
BISAC Codes
One subject code is required, but assigning three different subject codes is considered best practice to help ensure the broadest possible reach for your book. Why only give your book one opportunity to be found when you can give it three? Books are seldom about just one thing, so use the options that are the most relevant to your book. Look for codes that reflect the breadth and depth of your book's content. For example, if you wrote a romance, readers can't find it unless you've categorized it as "romance" with a subject code. It might also be considered "women's fiction" so you could also use that code. Don't stretch too far away from what your book is really about, though. Trying to sell your historical romance as straight history will help you lose readers, not gain them. Explore—don't exploit—opportunities to cross-promote.
Tips for Selecting the Right BISAC Codes
- Choose subject codes that accurately and clearly describe the content of your book as a whole. Do not select codes that pertain to only one chapter or reflect only a peripheral topic or theme of the work. If someone was looking for a book about a particular topic, imagine their disappointment if they only found one paragraph about it in your 200-page book. Be kind to your readers by being as honest as possible with your subject codes.
- The first subject code should be the best, most accurate, and most specific code possible. For example, the subject code HEALTH & FITNESS / Diet & Nutrition / Weight Loss is better than HEALTH & FITNESS / Diet & Nutrition / General or HEALTH & FITNESS / General. The more specific your code, the more targeted the reader it will attract. The more targeted the reader attracted to your book, the more likely you are to secure a purchase.
- If possible, select codes from multiple top-level subject categories to broaden discovery.
- For instance, you might classify actress and comedian Mindy Kaling’s memoir under both BIOGRAPHY & AUTOBIOGRAPHY and HUMOR.
- Avoid “General” codes whenever possible. The importance of this cannot be stressed enough. Never use FIC000000 FICTION / General unless there is genuinely no better, more specific code. It's rare that there will be no better code to describe your book than FICTION / General. Actually describe your book. If more specific codes can be used, selecting this code is a waste of one of your subject code opportunities.
- You do not need to include a “General” code if you have already selected a more specific code for a given category or subcategory. For example, if you have selected GARDENING/Flowers/Orchids, you do not need to also provide GARDENING/Flowers/General.
- Subject codes should be consistent across different formats of the same work, meaning the subject codes for your ebook version and print book version of the same title should match.
- Subject codes should match the audience of the book.
- Works intended for children ages 0-11 should have JUVENILE FICTION or JUVENILE NONFICTION codes.
- Works intended for young readers and teens ages 12-17 should have YOUNG ADULT FICTION or YOUNG ADULT NONFICTION codes.
- Fiction and nonfiction codes should not be used on the same title.
Thema Codes
Choosing the right Thema subject code and qualifier codes is a powerful way to make your book more discoverable in the Global Market. Themas were designed to help your book find both its broad, and very specific, audience around the world.
Tips for Selecting the Right Thema Codes
- Use up to three Thema subject codes. Selecting up to three codes allows for nuanced classification, providing readers worldwide with a clear understanding of your book's main topics and themes.
- List the primary subject code first. This helps convey the main theme.
- Do not use one-letter codes. For example: F for Fiction. This does not provide a significant enough level of detail. Instead, use FRH (Historical Romance" for a fictional love story set in 18th-century Paris.
- Use Thema qualifier codes in conjunction with Thema subject codes. Qualifier codes help refine the subject categories by identifiers such as place/location, time period, interest, and language.
Your BISAC and Thema subject codes tell others (human beings and online retailers) how to categorize your book. Take the time to do this right, because if you don't, no one else will do it for you. Booksellers and librarians skip over titles that make their jobs more difficult, and they typically don't dedicate additional time trying to determine where they would put your book on their shelves. If it's not clear to them at first glance, they'll move on. Don’t give anyone an excuse to pass your book by.
