The Modern Masters series...

is something few libraries in my area carry, which is unfortunate (this is another cheat entry, showing off my personal collection instead of actual library books).

They are great books -- interviews with masters of the comic book art form, like this one with Jeff Smith, full of bonus art you'd have trouble finding anywhere else. This one in particular is a great, in-depth interview. And Jeff Smith is, of course, the creator of Bone and if you do not have Bone in your library then something is seriously wrong!