In post-Revolutionary Mexico, the Indian was conceptualized as a problem that needed to be solved. Indians were believed to be weighing down the nation and thought to constitute an obstacle for fulfilling its promised modern future. Thus, the scientific study of indigenous peoples in Mexico became, in the 1930s, a focus of anthropologists, physicians, and other experts, who sought to learn more about indigenous populations in order to solve this "problem." In this paper I explore how this "problem-solving" was practiced, (...) how and why particular groups of people were used as subjects of inquiry and intervention, how they were selected, and how they enabled the production of knowledge deemed useful to... (shrink)