This book represents the first ever comprehensive study of the EU's foreign and security policy in Bosnia. Drawing on a wealth of fresh empirical material, it demonstrates that institutions are a key variable in explaining levels of common foreign security policy (CFSP) coherence and effectiveness over time. In doing so, it also sheds new light on the role that intergovernmental, bureaucratic and local political contestation have played in the formulation and implementation of a European foreign policy. The study concludes that the EU's involvement in Bosnia has not only had a significant impact on this Balkan country in its path from stabilisation to integration, but has also transformed the EU, its foreign and security policy and shaped the development of the EU's international identity along the way. The book will be of great interest to researchers and students of EU politics, International Relations and Bosnian politics.