Obviously Sally Fallon's. But what else? I just ordered "Real Food" by Nina Planck.
Hi! I would also second the recommendation of Nina Planck's books, both "Real Food" and the Mother & Baby one are good.
Super Nutrition for Babies: the Right Way for Optimal Health by Katherine Erlich
Traditional Foods Are Your Best Medicine by Ronald F. Schmid
Deep Nutrition: Why Your Genes Need Traditional Food by Catherine Shanahan
I also really enjoyed reading Nutrition and Physical Degeneration.