'Rigorously thought out, lucidly written, and empirically insightful, Julian Go's work dispatches arguments that the United States has not been an empire and sets out convincingly the changing nature of that empire. Far from being just a demonstration of what ought to have been obvious before now - the role of empire in American history - Go advances our understanding of the trajectory of empire and informs contemporary debates about the future of the United States and its global hegemony. This is a stunning application of transnational and comparative methods of analysis.' Ian Tyrrell, Scientia Professor of History, University of New South Wales