Excess: Fashion and Underground in the 80s is a really cool book with lots of great images (mostly from period magazines & ads) of the main fashion trends of the 80s (power dressing, new wave, japanese avant garde, punk, street fashion, etc) and also essays about and pictures of related trends in areas other than fashion.
Breaking the Mode features gorgeous avant-garde clothes from LACMA's collection
Belgian Fashion Design features dozens of Belgian designers from well-known like margiela, demeulemeester, bikkembergs, etc. to much more obscure. there was a copy at the strand when i went in this weekend. it is worth buying if you are inerested in avant-garde fashion.
if you can find them, old copies of european fashion mags (donna, vanity, vogue italia, etc.) are fun to look at. my favorite publications are back issues of book moda, gap collections (not related to the gap clothing chain!), fashion preview, and other periodicals like these (they are full of hundreds of runway photos for each season).