This article argues that a concern with social policy must be central rather than peripheral to sociology. Some sociologists wrongly regard policy analysis as inconsequential, or as an applied subject; others subordinate scientific to conventional, and highly restricted, interpretations of the concept. Both thereby fail to play a positive role in explaining how society came to be what it is and how it could be changed for the better. The role of the state in engineering social structure, particularly social stratification, and in controlling the direction of social change has been, as a consequence, underestimated. This article reviews in outline the history and future of the study of social policy.