This paper considers ways of thinking about causes and prevention that could guide epidemiology beyond the present era. Discontent with modern epidemiology, in the face of its substantial achievements, is taken as a sign that the guiding principles of the discipline warrant reconsideration. To begin this task, current practices are placed within an historical perspective, in a review of the dominant ideas of successive eras in epidemiology. Then the premises and constraints of the present era of chronic disease epidemiology, with its risk factor paradigm, are specified. Finally, elements of a causal paradigm for an emerging era are proposed. This paradigm encourages thinking about causes at multiple levels of organization and within the historical context of both societies and individuals. The proposed approach aims to preserve and build on the contributions of past eras, as well as the present one.