This book provides a detailed application of identity theory to contemporary questions of extremism, radicalization and security. The analysis considers how identity forms a central aspect of notions of extremism and security in Western societies, as articulated both by political leaders, the media and the government. It also takes a close and critical look at counter-extremism policy in contemporary Western society. With its detailed and empirical approach to these questions, this book is an accessible and invaluable resource for academics, practitioners, policy-makers and general readers keen to establish a deeper understanding of the key societal security threats of the day.