Before the turn of the century, few states used immigration detention. Today, nearly every state around the world has adopted immigration detention policy in some form. States practice detention as a means to address both the accelerating numbers of people crossing their borders, and the populations residing in their states without authorisation. This edited volume examines the contemporary diffusion of immigration detention policy throughout the world and the impact of this expansion on the prospects of protection for people seeking asylum. It includes contributions by immigration detention experts working in Australasia, the Americas, Europe, Africa and the Middle East. It is the first to set out a systematic comparison of immigration detention policy across these regions and to examine how immigration detention has become a ubiquitous part of border and immigration control strategies globally. In so doing, the volume presents a global perspective on the diversity of immigration detention policies and practices, how these circumstances developed, and the human impact of states exchanging individuals’ rights to liberty for the collective assurance of border and immigration control. This text will be of key interest to scholars, students and practitioners of immigration, migration, public administration, comparative policy studies, comparative politics and international political economy.