This book examines how Provincial Reconstruction Teams sought to stabilise Afghanistan’s provinces by combining security operations with reconstruction and development initiatives during 2002–15. Drawing on extensive academic and policy literature, as well as interviews with practitioners and officials from NATO member states, the volume reveals how each nation adapted the security–development nexus to its own priorities, with varying results. The book bridges theory and practice, showing how development strategies often faltered in high-risk environments and how rigid military structures struggled to support civilian goals. It also proposes a new analytical framework embedded in the theoretical manifestation of the security-development nexus for studying civil–military missions, offering lessons that remain vital for today’s peacebuilding and crisis management operations. Through rich case studies and clear insights, the book ultimately challenges one-size-fits-all approaches to reconstruction and demonstrates why understanding the balance between security and development is key to rebuilding societies after conflict. The book will be of much interest to students of security studies, conflict resolution, development studies and IR in general