In setting an agenda for policy sciences, Harold Lasswell argued that the field would be shaped by its contextuality, problem orientation, and methodological diversity. The review of developments in the field in this article shows that scholars have divided into positivist and post-positivist orientations that employ multiple frameworks and models. I argue that theoretical diversity should be expected and welcomed given the complexity of policy processes and phenomena. The article encourages positivists and post-positivists alike to allow the problem being studied to drive analysis and to seek ways to integrate different theoretical and methodological approaches.