Here's a list of some of interesting books I've read or browsed:
The Native Foods Restaurant Cookbook (a little self promtion :-) )
Mad Cowboy by Howard Lyman
Food Inc. by Peter Pringle
Dominion by Matthew Scully (former speech writer for Prez Bush)
The China Diet by T. Colin Campbell
Diet For A New America by John Robbins
Fast Food Nation by Eric Schlosser
The Web of Life by Fritjof Capra
Free the Animals by Ingrid Newkirk
Autobiography of a Yogi by Paramahansa Yogananda
If the Buddha Dated by Charlotte Kasl, Ph. D. (hey if there's a better way...gotta try it!)
Bury the Chains by Adam Hochschild-great book about the people that began to stop slavery and really the beginning of activism
as we know it today. Hochschild started Mother Jones magazine.