In one of the most important contributions to the study of Roman imperialism to appear in recent years, Robert Kallet-Marx argues for a less simplistic, more fluid understanding of the evolution of Roman power in the Balkans, Greece, and Asia Minor. He distinguishes between hegemony - the ability of the Romans to command obedience on the basis of a real or implied military threat - and the later phenomenon of empire, demonstrating that Roman imperium was not the result of the sudden imposition of geographically defined provinces or permanent armies. Rather, the integration of the Greek world into a Roman imperial system was a complex process of evolution requiring mutual adaptation by both Romans and Greeks.