The changing nature of security, the enlargement of European institutions and the evolving functions of the EU have been key developments in post-Cold War Europe. This book blends these three crucial developments in a sophisticated and illuminating manner. It assesses the impact of EU enlargement on both pre-existing security arrangements and key relationships with the EU’s new partners and ‘neighbours’. It also investigates both hard and soft, and internal and external security issues, ranging from military intervention to terrorism and from organised crime to human rights. From this it concludes that enlargement has both positive and negative implications for European security. Completing the analysis, this study examines the evolving security relationships with key states, regions and international organisations in the EU’s ‘neighbourhood’. The examination of relations with Turkey, Russia, Ukraine, the Greater Middle East and the Balkans provides a sense of the direction in which European security politics is moving.