''With unparalleled insight and urgency, Ebner reveals the dangerous spread of extremist beliefs. This book is a must-read for anyone who wants to understand the terrifying new reality we face'' - Eliot Higgins, author of We Are Bellingcat

''A sober and sobering read that helps disentangle an important though often misunderstood phenomenon'' - Brendan Daly

''A timely and frighteningly revealing book. It should be on the shelves of every Western spy agency working to defeat extremist ideologies'' - Richard Kerbaj, author of The Secret History of the Five Eyes

''A haunting and essential account of how so many people around the world have embraced extreme ideas'' - Cynthia Miller-Idriss

''Piercingly revelatory ... a tour de force'' - Carl Miller, author of The Death of the Gods