The last third of the twentieth century was ushered in by a set ofevents—wars, rebellions, ?nally economic crisis—that dealt a crushing blow to the previously dominant paradigm in U.S. social science, the structural-functionalist modernizationism elaborated by Talcott Parsons and his students. Within sociology, the site of much social science innovation in the post-war period, a notable splintering occurred. Already under-way in the early nineteen-sixties, this splintering was accelerated by the tumultuous events later in that decade. One of the splinters which has grown and developed most rapidly and fruitfully over the past decade has been the world-systems perspective, a formidable synthesis of continental historicism, “Third World” radicalism, and Marxism. The principal exponent of this perspective has been Immanuel Wallerstein (b. 1930). whose work has built upon and in turn has stimulated advances in both historical sociology and the study of contemporary “development.”