Based on customer requests.
The heavyweight champion.
"Where's your nonfiction section?"
"Where do you keep your old books? I mean REALLY old!"
"What section do you keep your popular books in?"
"Where are your classics?"
Mostly this means they're looking for fiction.
Old people still use it correctly, referring to the Greeks & Romans.
"Where are the Christian books?
Always said defiantly, like they're waiting for you to mark your place in Aliester Crowley's autobiography with a bookmark of tattooed human skin so you can scream GET OUT! at them in a Hollywood special effects voice.