This book offers an innovative account of Prevent, Britain's counter-radicalisation strategy, situating it as a novel form of power that has played a central role in the production and the policing of contemporary British identity. Drawing on interviews with those at the heart of Prevent's development, the book provides readers with an in-depth history and conceptualisation of the policy. The book demonstrates that Prevent is an ambitious new way of thinking about violence that has led to the creation of a radical new role for the state: tackling vulnerability to radicalisation. Detailing the history of the policy, and the concepts and practices that have been developed within Prevent, this book critically engages with the assumptions on which they are based and the forms of power they mobilise.