What does it mean to be 'vulnerable'? Exploring the rise of 'vulnerability' as an organising concept in migration detention, integration, public health, national security and social policy, this volume reveals the blurring of welfare state logics with national security ends. Governments and international agencies use the language of vulnerability to identify needy constituents and communities, but also to frame that need as potentially dangerous. Using international case studies this book shows how vulnerability governance permeates policy sectors - transforming the methods used to govern, problematise and resolve - bringing questions of risk management and security into social policy, but simultaneously brings social policy sectors into counterterrorism delivery. The combination of welfare state and security logics brings interventions deeper into societies, securitising communities and individuals on account of their needs, governing the social through security politics.