Contemporary global politics poses urgent challenges – from humanitarian, migratory and environmental problems to economic, religious and military conflicts – that strain not only existing political systems and resources, but also the frameworks and concepts of political thinking. The standard cosmopolitan response is to invoke a sense of global community, governed by such principles as human rights or humanitarianism, free or fair trade, global equality, multiculturalism, or extra-national democracy. Yet, the contours, grounds and implications of such a global community remain notoriously controversial, and it risks abstracting precisely from the particular and conflictual character of the challenges which global politics poses. The contributions to this collection undertake to develop a more fruitful cosmopolitan response to global political challenges, one that roots cosmopolitanism in the particularity and conflict of global politics itself. They argue that this ‘contestatory’ cosmopolitanism must be dialectical, agonistic and democratic: that is, its concepts and principles must be developed immanently and critically out of prevailing normative resources; they must reflect and acknowledge their antagonistic roots; and they must be the result of participatory and self-determining publics. In elaborating this alternative, the contributions also return to neglected cosmopolitan theorists like Hegel, Adorno, Arendt, Camus, Derrida, and Mouffe, and reconsider mainstream figures such as Kant and Habermas. This collection was originally published as a special edition of Critical Horizons.