A collection of essays on the politics of boundaries, this book addresses a broad range of cases, some geographical, some legal, and some involving less tangible practices of inclusion and exclusion. The book begins by exploring the boundary between modern Western forms of international relations and their constitutive outsides. Beyond this, the author engages with relations between subjectivity and security, security and nature, social movements and a world politics, as well as the politics of spatiotemporal dislocation. Two chapters address the work of Thomas Hobbes and Max Weber as exemplary accounts of the relationship between boundaries and the constitution of modern forms of politics. Each chapter speaks not only to the politics of specific boundary practices, but also to the limits within which modern politics has been shaped in relation to claims about spatiality, temporality, sovereignty and subjectivity. In this way, the book draws attention to a pervasive account of a scalar order of higher and lower that has shaped more familiar distinctions between internality and externality. Offering an analysis of the relation between concepts of internationalism, imperialism and exceptionalism, as well as the implications of spatiotemporal dislocation for claims about democracy, the book links contemporary claims about the transformation of boundaries to various ways in which political life is said to be in crisis and in need of novel forms of critique. Brought up to date by a new and extensive introductory essay and an assessment of the status of political judgement after 9/11, this book is essential reading for students and scholars of politics, international relations, political theory and political sociology.