Cosmopolitanism is one of the most venerable intellectual traditions in the history of political philosophy. From the ancient Greek Diogenes’ claim to be a citizen of the world through to Kant’s Enlightenment vision of a world government and even into our own time, the idea of cosmopolitanism has stirred the moral imagination of many throughout history. Arguably the Brexit referendum result and the election of Donald Trump in 2016 marked the first major public repudiation of the transnational, globalizing cosmopolitan ideals that have arguably dominated politics in the liberal democratic West since the end of the Cold War. This volume reconsiders cosmopolitanism and its discontents in the age of Brexit and Trump by bringing together the great thinkers in the history of political philosophy and contemporary reflections on the problems and possibilities of international relations, human rights, multiculturalism, and regnant theories of democracy and the state.