Why do some people switch from one extremist political or religious ideology to join the group they previously considered their greatest enemy? This book is the first study to explore the extraordinary stories of these side-switchers to understand how radicalization works and how extremist views can change.

Explore the world of radicalization through the stories of those who switched between extreme political or religious ideologies.

'Theoretically rich and storyline-driven, From Traitor to Zealot is an instant classic of the field. Koehler shines a bright light on a counter-intuitive phenomenon many are anecdotally aware of - extremists who switch sides - but the book will surprise many by outlining how common, complex and dramatical the process is.' Paul Gill, Professor of Security and Crime Science, University College London, UK