The early twenty-first century has been defined by a rise in Islamist radicalisation and a concurrent rise in far right extremism. This book explores the interaction between the 'new' far right and Islamist extremists and considers the consequences for the global terror threat. Julia Ebner argues that far right and Islamist extremist narratives - 'The West is at war with Islam' and 'Muslims are at war with the West' - complement each other perfectly, making the two extremes rhetorical allies and building a spiralling torrent of hatred - 'The Rage'. By looking at extremist movements both online and offline, she shows how far right and Islamist extremists have succeeded in penetrating each other's echo chambers as a result of their mutually useful messages. Based on first-hand interviews, this book introduces readers to the world of reciprocal radicalisation and the hotbeds of extremism that have developed - with potentially disastrous consequences - in the UK, Europe and the US. With a new foreword, this new edition discusses the events of recent years, and how the phenomenon of reciprocal radicalisation – the interplay between Islamist and far-right extremism – has become more pronounced and, sadly, more dangerous.