Policing Transnational Protest offers an original perspective on the history of police surveillance of anticolonial activists in France, Britain, and Germany in the first half of the twentieth century. Tracing the undertakings of anticolonial activists from Asia, Africa, and the Middle East in Europe and reconstructing the reaction of European governments, it illuminates the increasing cooperation of the police and secret services to monitor the activities of the "oriental revolutionaries" and curb their room to maneuver. But those efforts had an unintended inflammatory effect, provoking both supporters and opponents of colonial rule to understand the conflict in increasingly global and trans-imperial terms. The surveillance also exacerbated tensions between Europeans friendly to the anticolonial cause, and those who prioritized imperial security over civil liberties and national sovereignty. Tracking growing levels of transnational government cooperation against anticolonialists, this book pays special attention to Germany, where many activists were able to carry out their political work in relative safety after escaping surveillance in Britain and France. By analyzing the emergence of ever more sophisticated counter-terrorism schemes and surveillance apparatuses, Brückenhaus also contributes a pre-history of similar phenomena characterizing the post-9/11 world. He shows how, then as now, an intensification of a "war on terror" went hand in hand with concerns about encroachments on civil liberties, often expressed in open protest against such governance measures. Policing Transnational Protest informs current debates about intelligence gathering and surveillance in several European countries as well as their new cooperative partner, the United States.