and her brother devoted most of his life to the Bushmen. In the 1950s the Ju/wasi maintained their ancient nomadic culture in near isolation. Except for bits of metal they obtained in trade and used for arrowheads, the Ju/wasi made everything they needed from local material. They did not farm and had no domestic animals, but obtained all their food from hunting and gathering. They were the last people on earth, says Thomas, to follow the "Old Way," a way of life that depends on knowledge handed down one-to-one from generation to generation. The Old Way depends on intimacy between habitat and humanity. Thomas' book is not a scientific study or a memoir, but a bit of both, as well as a celebration and lament for a culture now gone. It's also a thoughtful reflection on how the Old Way shaped our species from the time we came down out of the trees and stepped on to the Savannah. Water, says Thomas, controlled the size of human hunter-gatherer groups, and that remained true among the Ju/wasi. Rain was scarce, and water holes passed down through families. Though children were betrothed young, they did not cohabit until the girl reached menarche - about age 17 - and the average age for bearing a first child was 19. Similarly, though no birth control was used, women bore children about four years apart and seldom had more than four. This was just what could be sustained, without starvation or overburdening the mother or