This volume provides a framework for analyzing security sector reform under international tutelage. Following violent conflict and military interventions, international organizations or coalitions of countries increasingly engage in post-conflict reconstruction. Part of the international post-conflict agenda is the ‘reconstruction’ or ‘reform’ of the security sector (SSR). In post-conflict situations, the security sector is often characterized by politicization, ethnicization, corruption of the security services, excessive military spending, lack of professionalism, poor oversight and inefficient allocation of resources. At the same time, there is great need for effective and efficient (re-)establishment of a legitimate monopoly of force. While initially this is in the purview of the external intervention forces, they also face the task of the building up of effective, efficient accountable and democratically legitimized security forces as quickly as possible. The contributors analyze six pertinent cases: Afghanistan, Bosnia-Herzegovina, Haiti, Kosovo, Sierra Leone and Timor Leste, focusing on issues such as priorities for security and for security sector reform, sequencing of reconstruction and reform, tensions between requirements of security and security governance and the interaction of domestic and external actors in security sector reform. This book was previously published as a special issue of International Peacekeeping.