The paper extends the concepts and framework of the life-course perspective and applies them to the development of criminology as a discipline. At the most general level, the life course may be defined as "pathways through the age-differentiated life span" (Elder, 1985). Life-course theory and research focus on trajectories (long-term patterns) and transitions (short-term events) over time. The major concepts from the life course include a focus on continuity; change, especially turning points; age (period and cohort effects); and both internal and external forces that may shape life-course development. Elder (1998) has identified four life-course principles in the study of lives. This paper uses these principles as a framework for conceptualizing and understanding the life course of criminology. The first principle is that the life course of individuals is embedded in and shaped by the historical times and places they experience over their life time. The second principle is that the developmental impact of a succession of life transitions or events is contingent on when they occur in a person's life. The third principle is that lives are lived interdependently, and social and historical influences are expressed through this network of shared relationships. The fourth principle is that individuals construct their own life course through the choices and actions they take within the opportunities and constraints of history and social circumstances. A discussion of the developmental course of criminology considers three eras or life-course phases in criminology in the United States over the last 100 years. The first era covers the period from 1900 to 1930 and is characterized by the multiple-factor approach. The second era covers the period from 1930 to 1960, which this paper calls the "Golden Age of Theory." In this era the theories of Merton, Sutherland, Cohen, and Cloward and Ohlin dominated the scene. The third era was the period from 1960 to 2000, which was characterized by extensive theory testing of the dominant theories, using largely empirical methods. This era also witnessed new theoretical developments grounded in research and facts about crime. The paper then discusses continuity in the life course of criminology, as well as evidence of significant change. Turning points addressed are the work of Clifford Shaw and Henry McKay, the Sutherland-Glueck debate, the "Causes of Delinquency" by Travis Hirschi, the Philadelphia birth cohort study by Marvin Wolfgang, and the work of James Q. Wilson. The paper concludes with a discussion of policy and theory, as it draws on the history of criminology to revisit this topic. The challenge for the future is identified as bringing theory, research, and policy together for a meaningful dialog. The paper argues that this can best be done by creating a mission statement for criminology. This mission statement must emphasize that ideas matter, and they are the core of what criminology does. Further, the ideas put forth must be grounded in the history of the field, since the quality of the ideas of the present must reflect an informed analysis of and an appreciation for the ideas of those who have come before us. 75 references