This book examines how social media has transformed extremist discourse. Drawing on ISIS and their sophisticated use of social media platforms and PR concepts, it explores the ways in which the outfit was able to recruit, mobilise and spread fundamentalist propaganda in regions where it had little physical presence. One of the first studies to draw a link between international diplomacy, the rise of fundamentalism and public relations, this book will be of great interest to scholars and researchers of defence and strategic studies, especially those working on ISIS propaganda, Middle East Studies, media studies, digital humanities, communication studies, public relations and international relations, as well general readers.