When you walk into your favorite bookstore, do you roam about looking at all the books in all the sections? Probably not. I’ll bet you head for the area labeled with your favorite reads: romance, mystery, teen fiction, etc. Genre labels were created so that bookstores would know where to shelve the books to enable readers to find the books we love the most.
With the popularity of cross-genre books today, have you ever been confused about what label you should put on the book you are reading or writing? Literary agent Lucienne Diver of the Knight Agency gives a great detailed explanation of genres and sub-genres in this blog post.