Increasingly, European and other Western states have sought to control the movement of refugees outside their borders. To do this, states have adopted a variety of measures - including carrier sanctions, interception of migrants at sea, posting of immigration officers in foreign countries and external processing of asylum-seekers. This book focuses on the legal implications of external mechanisms of migration control for the protection of refugees and irregular migrants. The book explores how refugee and human rights law has responded to the new measures adopted by states, and how states have sought cooperation with other actors in the context of migration control. The book defends the thesis that when European states attempt to control the movement of migrants outside their territories, they remain responsible under international law for protecting the rights of refugees as well as their general human rights. It also identifies how EU law governs and constrains the various types of pre-border migration enforcement employed by EU Member States, and examines how unfolding practices of external migration control conform with international law. This is a work which will be essential reading for scholars and practitioners of asylum and refugee law throughout Europe and the wider world.