Resistance to malaria. Blue eyes. Lactose tolerance. What do all of these traits have in common? Every one of them has emerged in the last 10,000 years. Scientists have long believed that the "great leap forward" that occurred some 40,000 to 50,000 years ago marked end of significant biological evolution in humans. In this original account of our evolutionary history, top scholars Gregory Cochran and Henry Harpending reject this conventional wisdom...