+1 to Berto's "Upgrading Your Bike". Some nights i'll announce to my family "I'll be in the sunroom reading Upgrading Your Bike". My daughter rolls her eyes in embarassment for my geekiness.

Right now I've got "Glenn's New Complete Bicycle Manual " on loan from the library. It is a vintage bike repair bonanza--ie,separate sections on how to overhaul Suntour, Huret, Shimano, and Campy rd's. I'll definitely be trying to buy this one off ABE Books.

I also like one of the most primitive books in this genre---Everybody's Bike Book, originally aimed at mechanically clueless bike owners during the 70's bike boom.