Or Rosenboim, a historian of political thought at Cambridge, recovers the largely forgotten debates about world order that took place during the 1940s as thinkers grappled with the crisis of the nation-state system. While conventional history focuses on the creation of the United Nations and the Cold War's emergence, Rosenboim examines the more ambitious visions that proliferated before bipolarity foreclosed alternatives. She traces how intellectuals including H.G. Wells, Owen Lattimore, Barbara Wootton, and lesser-known figures developed competing models of global governance: world federalism, regionalism, functional international agencies, and various combinations. These thinkers took seriously the possibility that the nation-state had become obsolete and that new political forms were necessary and possible. Rosenboim shows how their ideas drew on different intellectual traditions--liberalism, socialism, federalism, and geopolitics--and how they responded to the specific circumstances of world war and decolonization. The book traces why these radical visions were marginalized as the Cold War made world government seem either impossible or threatening, leaving a narrower range of options for international cooperation. By recovering this moment of political imagination, Rosenboim provides historical perspective on contemporary debates about global governance and demonstrates that current arrangements were not inevitable but emerged from choices made in specific circumstances.