Nineteenth-century foundations -- Grand projects, 1898-1920 -- The American way in a fragmenting world, 1921-1940 -- Reaching for geopolitical dominance, 1941-1968 -- In the American image, 1941-1968 -- The Third-World challenge, 1941-1968 -- Disoriented giant, 1968-1991 -- The neoliberal triumph, 1991- -- Conclusion: Hegemony in question.