The current situation in health care organizations, among providers and for people, dramatically challenges the "business as usual" roles of medicine, government, insurance companies, the community, and the university. Health care reform marks the first attempt in a century to consider a reconstruction of the social contract between society and medicine. While sociology stands as one of the earliest social sciences to systematically study the health care arena and create a health-focused subfield, there is a perception, not without support, of a desertion of identity from within, an encroachment by other areas from without, and abandonment by the parent discipline. We argue that these situations in medical arenas and in research fields require serious rethinking. The key lies in understanding how these phenomena are related to each other and to larger social forces, and how they offer opportunities, rather than signal limitations, to medical sociologists. We turn to the theoretical tools of sociology to help unravel the complicated challenges that face both policymakers and researchers. After framing these issues in a sociology of knowledge perspective, we use the case of "utilization theory" to illustrate the connections between society and systems of care (as well as studies of them) and to create a future agenda. We end by raising three basic questions: (1) Why is a sociological perspective critical to the understanding of change and reform in health care? (2) Why is medical sociology critical to the survival of the general sociological enterprise? and (3) Why is general sociology critical to the research agenda in medical sociology? [ABSTRACT FROM AUTHOR]