This book examines the structure and ideology of all the main leftist groups in Iran. It considers their role in the Revolution, and analyses their relations with Khomeini and his colleagues. It also explains why the majority of the leftist organisations had defected from the Islamic regime by the summer of 1981. A second important theme of the book is the way in which the Soviet Union responded to the treatment of the Left by the Islamic government. Based on extensive analysis of original source material in Farsi and other languages and numerous interviews with leftist leaders and participants, the book provides a detailed portrait of the Left in contemporary Iran.