The history of Community Psychology is not just a history of professional developments in the field but also a history of the interaction between social events and the accomplishments of community psychologists. In this chapter, we document the evolution of community psychology within the context of events in U.S. history beginning at least twenty years before the field was founded. We propose that earlier cultural and historical events and circumstances are important contexts for the founding of the field at the 1965 Swampscott Conference. Furthermore, these same cultural and historical events have also provided a context for the emergence of three major and defining domains of community psychology. The first, working with the strengths of persons and communities, has served as a guiding value for the field's development. Second, ecological theory, has provided a theoretical framework for the work that community psychologists do. Finally, designing and conducting preventive interventions has become the primary way in which community psychology research has been translated into action. For each of these domains, we provide a review of significant empirical and theoretical developments in the filed. We conclude the chapter by providing critical observations and suggestions for future directions.