Policymakers are now writing about ‘The End of Pax Americana’ in Foreign Affairs (November/December 2015). This is a long way from talk of ‘The Reluctant Imperialist: Terrorism, Failed States, and the Case for American Empire’, which featured in the same journal (March/April 2002), yet it should not dissuade (non-)subscribers from reading a book written at the height of what authors of a Nation magazine article labelled ‘An Imperial Moment’ (23 December 2002). I say this since Niall Ferguson’s Colossus: The Rise and Fall of the American Empire (2005 [2004]) is timeless. Notwithstanding being born in revolution against imperial control, Ferguson elucidates, the founding states were unexceptional when empire-building out west; much like traditional European land-grabbing empires, the Founding Fathers and their successors sought to mark territory in imperial red (white and blue). After discussing ‘the imperialism of anti-imperialism’ and dismissing (rightly) the notion of a “clash of civilisations” between Islam and the west, the author discerns seven ‘characteristic phases of American engagement’ before directing readers to three ‘deficits’ – economic, manpower and attention – by way of an explanation as to why informal empire has not developed more formally overseas. Colossus is a long way from Ferguson’s magnum opus, the two-volume history of the Rothschild family, since – as a sequel-of-sorts to Empire – it contains no dusty-fingered research. Despite being based on secondary-source material, though, it nonetheless remains primary reading for students and scholars interested in what the author (persuasively) contends are the vices of American isolationism and the virtues of vigorous engagement.