Lighten Up!

Lighten Up!: A Complete Handbook for Light and Ultralight Backpacking (Falcon Guide) - Don Ladigin, Don Ladigan, Mike Clelland

A good introduction to lightweight backpacking. I already knew most of the information, but this would still be an excellent book to read if you've been toting around 50 lbs every backcountry trip and you want to save your knees and lighten your load a lot.