...a magnificent achievement, and a landmark in at least three distinct fields: anthropological demography, human evolutionary ecology, and hunter-gatherer studies...." -- Evolutionary Anthropology The Ache, whose life history the authors recounts, are a small indigenous population of hunters and gatherers living in the neotropical rainforest of eastern Paraguay. This is part exemplary ethnography of the Ache and in larger part uses this population to make a signal contribution to human evolutionary ecology.