Does participation in a market economy help or hurt indigenous peoples? There have been few quantitative studies that have addressed this question, which is nonetheless a topic of considerable debate in academia and the media as well as among policymakers. Investigating five different lowland Amerindian societies of tropical Latin America - all of which are experiencing deep changes as they modernize - a team of natural and social scientists takes a first step in filling this gap. Using multivariate estimations to examine the effect of markets on a broad range of areas - including health, conservation of flora and fauna, deforestation, leisure, folk knowledge, reciprocity, private time preference - the author finds ambiguous effects but in general concludes that markets do not erode the quality of life.