I can't speak highly enough of of these books and authors.  I might as well be their poster girl, I've told so many people about them:

"Going Wild in the Kitchen," Leslie Cerier.  You've gotta love the title, right?  The recipes are all good too.  I've test run a number of them and have been pleased with every one.  Of particular interest are the wheat-free desserts.  The Banana Chocolate Chip cake is ridiculous. 

"Nourishing Traditions" Sally Fallon.  This is a text book on lost cooking methods.  It's a reference book of tremendous value.  I really can't say enough good things about it.  I'll be studying its contents for years to come.

"Real Food: What to Eat and Why" Nina Planck.  Nina has a fresh, charming, very New York writing style, and this book is meticulously researched.  Like Nourishing Traditions, it defends traditional foods and encourages recuperating the eating practices of our fore-mothers.  The clif-notes version:  if your grandma wouldn't recognize what you're eating as food, don't eat it.  Unlike the previous two books, it does not have recipes.