What is international relations (IR) theory? Is it an arcane academic enterprise or relevant to the real world? What do we mean by theory? What kinds of knowledge do theories seek or represent? How do they stipulate it should be found? How should we evaluate any resulting knowledge claims? What do answers to these questions tell us about the theory project in IR, and more generally in the social sciences? I address all of these questions in this book and set of companion videos. The videos can be accessed free of charge at nedlebow.com I cover epistemological ground with which you may be familiar, but perhaps not. I lay bare and query the assumptions of positivist and interpretivist approaches to knowledge in general and to IR in particular. I identify and explore the most important inner tensions of these epistemologies and question the assumptions they make about the world. I identify problems that need to be addressed, suggest some possible strategies or reformulations toward this end, and how adherents of the two epistemologies might learn from one other. Above all, I am interested in the extent to which IR theories can tell us something useful about the world. This book is as about theory in IR, not about theories of IR. This distinction is an important one. It focuses on theory, what it is, purports to be, and how it organizes our understanding of the discipline and the world. It engages some IR theories and research programs, but only as illustrations or for the insights they offer into the questions I have posed. It differs significantly from most other books on IR theory"--