Genres and subgenres!
Authors, do you know what genre your book is? It is definitely more than just "fiction" or "nonfiction." There are subgenres, and maybe a mix of several. If you are an author, and write in multi-genres, then you are a multi-genre author, and should market your author's brand as such.
Amy's Bookshelf Reviews has compiled a list of genres, and then the categories where the reviews that are posted in, are listed. This page can be used as a resource for authors.
Genre knowledge is important. Authors need to know which genres their stories fit in. Authors may think that some genres are interchangeable, but that may not be the case. For instance, a supernatural genre, which has creatures, monsters, devils and the like, is not the same as a paranormal, where they are ghosts and spirits, and things that go bump in the night.
Why is getting the correct genres important?
It is not just literary fiction. It is not just nonfiction, true crime, or children. The author needs to know the target audience. The author also needs to know this when trying to get a publisher, editor, agent or publicist.
If the work has more than one genre, list all the genres you think fit the story, and then look at the main genre (which describes it the most ... again not nonfiction or fiction) and then look at sub genres, but the ones that fit the most. If you have a crime genre, with a subplot of serial killers, and the main character has a relationship with someone, it doesn't necessary mean it's also a romance.
I hope this helps. It is very important for marketing, and querying the correct professional. (Even designing the book cover.