Honestly, library books tend to be better than random stuff in Barnes and Noble because if it wasn't checked out, it probably would've already been scrubbed from the selection (libraries have limited space), so instead of just getting whatever books were published in the last 2 years, you get books that were published in the last 200 years, and only the more interesting ones. Additionally, the Dewey Decimal system, or its replacement (don't remember what it's called), sorts stuff by similar topic, so if you're already in a section that is interesting to you, any nearby random book also is likely interesting.

This is why I like still going to physical libraries. Also, lack of user-hostile interfaces.