More than 12,000 years ago, in one of the greatest triumphs of prehistory, humans colonized North America, a continent that was then truly a new world. Just when and how they did so has been one of the most perplexing and controversial questions in archaeology. This dazzling, cutting-edge synthesis, written for a wide audience by an archaeologist who has long been at the center of these debates, tells the scientific story of the first Americans: where...