Based on original research in the Public Records Office, this book examines the world of the secret service in the last days of the British Empire before and immediately after World War I. Beset by anti-Western and anti-imperialist movements, the Empire fought back against threats to its survival, using the SIS (Special Intelligence Service) and its cast of amateur spies. This book shows what the secret service was really up to in these years and reveals the personalities of those recruited to work as undercover agents. It explores threats to Imperial security from Islamic extremists, communists and rival Western powers. This book features psychological, as well as historical, insights and offers a novel use of archival material in the history of intelligence.