Michael C. Clatts is a medical anthropologist whose principal area of interest is the study of social change, particularly the use of qualitative research methodologies in the formulation, implementation, and evaluation of social change programs. He began research relating to AIDS in 1982 while working with the National Institutes of Health on the first multi-city epidemiological study of risk factors for HIV infection. Since 1987, he has been conducting street-based ethnographic studies relating to the development, implementation, and evaluation of AIDS prevention programs in New York City. His current activities include a NIDA-funded AIDS prevention project targeted to drug injectors in Harlem, a NIDA-funded AIDS prevention project targeted to high-risk youth in mid-town Manhattan, and a CDC-funded evaluation study of AIDS outreach and prevention services targeted to homeless and runaway youth. He is a member of the AIDS and Anthropology Task Force and serves on the Steering Committee of the AIDS and Anthropology Research Group.