Most of us take for granted the features of our modern society, from air travel and telecommunications to literacy and obesity. Yet for nearly all of its six million years of existence, human society had none of these things. While the gulf that divides us from our primitive ancestors may seem unbridgeably wide, we can glimpse much of our former lifestyle in those largely traditional societies still or recently in existence. Societies like those of the New Guinea Highlanders remind us that it was only yesterday—in evolutionary time—when everything changed and that we moderns still possess bodies and social practices often better adapted to traditional than to modern conditions.The World Until Yesterday provides a mesmerizing firsthand picture of the human past as it had been for millions of years—a past that has mostly vanished—and considers what the differences between that past and our present mean for our lives today.