Book Industry Standards and Communications, otherwise known as BISAC, is a standardized category and topic system for books. Standardized codes help booksellers, libraries, researchers, and shoppers find books regarding specific subjects. The expansive list of categories is maintained by the Book Industry Study Group (BISG). The BISG provides a FAQ on BISAC code's selection that you might find helpful.At minimum, Lulu requires the General category to be selected for all books sold through the Lulu Bookstore. If you intend to use Lulu’s Global Distribution service, we require at minimum one sub-category as well. For example, a BISAC category for a project in Global Distribution could look like this:FIC022020 FICTION / Mystery & Detective / Police ProceduralThe above example would be appropriate for a mystery novel about a police officer solving a crime.Per BISG standards, Lulu allows you to apply up to three total BISAC categories to accurately categorize your project.Note: Our staff is not able to provide guidance on which code you should choose for your book. We are not subject matter experts on a book we've not read. As a result, we aren't in a good position to select the code for your book. You're the expert on your book and are best suited to select the right code for it.