Abstract: Revised estimates of world GDP, population and GDP per capita published by Angus Maddison (2001) make possible a quantitative reexamination of the trajectory of the United States in world historical perspective and comparisons between the U.S. economic hegemony of the twentieth century with the Dutch hegemony of the seventeenth century and the British hegemony of the nineteenth century. We also track the trajectories of challengers to reflect on the future of hegemonic rivalry.