To keep items organized on a site, administrators often use the built-in WordPress categories and terms to identify similar items. Looking back at the Book Reviews system that we have been putting in place so far in this chapter, a type of categorization that would be helpful is a book type (for example, Science Fiction, Documentary, Fiction, Poetry, and so on).

This recipe shows how to create a new category (known as a taxonomy in the WordPress backend) and associate it with the Book Review custom post type.