This book examines the question of how our knowledge of social life affects, and ought to affect, our way of living it. In so doing, it critically discusses two epistemological models of social science - the positivist and the interpretive - from the viewpoint of the political theories which, it is argued, are implicit in these models; moreover, it proposes a third model - the critical - which is organised around an explicit account of the relation between social theory and practical life. The book has the special merit of being a good overview of the principal current ideas about the relation between social theory and political practice, as well as an attempt at providing a new and more satisfactory account of this relationship. To accomplish this task, it synthesises work from the analytic philosophy of social science with that of the neo-Marxism of the Frankfurt school.