Does a system of great powers necessarily imply a struggle for world primacy? Do great states merely hold onto what is theirs, or do they reach for more? Anthony D'Agostino offers a fascinating new answer to these questions through a fundamental reassessment of the international history of the first half of the twentieth century. From the spatial limits of a purely European great power politics the book looks out to the new horizon of world politics. From the time limits of 1914 to 1945 it considers the interface with nineteenth-century imperialism at one end and the impact of the world wars on the Cold War at the other. This is a global retelling of the expansion of Europe coming up against its limits in the most violent conflicts and explosive social movements yet known to history, the two world wars, the Great Depression, and the Russian and Chinese revolutions.