William F. Flack, Jr., Daniel R. Miller, and Morton Wiener What is schizophrenia?l This was the seemingly simple question posed to a diverse group of investigators asked to present their views at a conference sponsored by the Frances L. Hiatt School of Psychology at Clark University, Worcester, Massachusetts, in June, 1990. The plan was to have a small group of theoretically minded clinicians and investigators from different professions and orientations convene to discuss and debate conceptual and metatheoretical issues surrounding "schizophrenia." Instead of concentrating on the latest empirical findings, we were primarily interested in having a series of exchanges 2 about the very different meanings and uses of this concept. In our review of the literature on schizophrenia, we uncovered what seemed to us to be multiple, non-overlapping uses of the term. For some investigators, it appears to be used to specify certain kinds of people; for others, it is employed to refer to certain kinds of behaviors. For still others, the term is grounded in biochemical events, or in socioculturally specific actions. A number of alternatives are explored in the contributors' papers in this volume.