A conceptual framework for studying the prevention of human dysfunction is offered. On the basis of recent advances in research on the development of psychological disorders and methods of preventive intervention, generalizations about the relation of risk and protective factors to disorder are put forward, along with a set of principles for what may be identified as the science of prevention. Emerging themes from the study of human development, in general, need to be incorporated in the models for explaining and preventing serious problems of human adaptation. The article concludes with a set of recommendations for a national prevention research agenda.