During and after World War II, intellectuals and scholars in the United Kingdom and the United States engaged in a vigorous and wide-ranging debate about the future of world order as the global calamity forced the Western world to grapple with elemental questions about the character of modernity and the nature of democracy. This impressive book provides the best intellectual history yet of that tumultuous era. Some theorists, such as Raymond Aron, David Mitrany, and E. H. Carr, reimagined the role of the state. Others, such as Owen Lattimore and Nicholas Spykman, contemplated the effects of geography and regionalism. Clarence Streit pondered the possibilities of a union of democracies, Friedrich Hayek and Lionel Robbins debated the limits of welfare capitalism and economic federalism, and H. G. Wells and Michael Polanyi explored the transformative roles of science and technology. Rosenboim argues that what united these disparate thinkers was their shared conviction that the scale and scope of world politics were rapidly changing and that new ideas about political authority and cooperation were needed.