Posted 12/21/1999. Discusses the arrival of a new field of inquiry in prevention research. Two decades of research on the cognitive underpinnings of depression and health is now leading to an era where preventive trials take center stage. The knowledge accumulated through theory-driven observational and laboratory research in that earlier period is now stimulating preliminary models for preventive intervention through the conduct of preventive trials as well as tests of new hypotheses about the linkages between cognitive dispositions, depression, and health. It is increasingly clear that depression has great impact on human functioning and the costs of adverse health outcomes have now become a commonplace focus of public policy debates. The authors introduce the two articles in this volume and their commentaries which highlight the role psychological theory and research can play in the development of a preventive science. They also highlight the important link between emotional and physical health and how it can be illuminated by carefully designed and theoretically informed preventive trials. (PsycINFO Database Record (c) 2006 APA, all rights reserved)