The category of anarchy is conventionally associated with the emergence of an autonomous discipline of International Relations. Recently, Donnelly has argued that anarchy has never been central to IR. His criticism targets not just concepts of anarchy but theories of anarchy and thereby expresses an anti-theory ethos tacitly accepted in the discipline. As a form of conceptual atomism, this ethos is hostile to structuralist and normative theories. This article aims to reinstate theoretical holism against conceptual atomism and to defend the (...) enduring relevance of theories of international anarchy for IR. This is done by revisiting two classic, structuralist accounts of international anarchy articulated in Kenneth Waltz’s Theory of International Politics and Hedley Bull’s Anarchical Society. It will be shown that both represent coherent theoretical ‘wholes’ which reveal a more complex relationship between anarchy and hierar... (shrink)