One of our most influential anthropologists reevaluates her long and illustrious career by returning to her roots-and the roots of life as we know it When Elizabeth Marshall Thomas first arrived in Africa to live among the Kalahari San, or bushmen, it was 1950, she was nineteen years old, and these last surviving hunter-gatherers were living as humans had lived for 15,000 centuries. Thomas wound up writing about their world in a seminal work,The Harmless...