A lot of bookstores sort books by genre. Makes sense, right?
Mystery readers are going to tend to want to read, and therefore buy, mystery books.
Same goes for romance readers.
And Sci-Fi.
But some books are ambiguous about their genre - I didn't know Never Let Me Go was Sci-Fi, and it tends to be shelved in General Fiction.Plenty of thriller books have a romance storyline running through them (too many, says my dad).
And what about variation within genres? I read Sophie Hannah, and my dad reads James Patterson, and they're both shelved in Thriller/Mystery/Police/Murder or whatever the bookstore wants to go with, but I'm sure those who have read both wouldn't necessarily recommend them to the same people.
Do genres help or hinder?
Is your local bookstore (chain, independent or charity) separated into genres?
Is your library? Mine isn't beyond fiction, non-fiction and kids.