Among the various Muslim communities that were articulating their doctrinal positions in the early Islamic centuries, one in particular was known derisively as the Ghulat (‘extremists’). This was owing to their specific interpretation of Shiʿi Islam, which included divinisation of their Imams, and controversial religious ideas, such as the transmigration of souls. Active in Iraq in the 8th and 9th centuries, the Ghulat developed a complex worldview and produced a rich religious literature. Until now, understanding of this community has mainly relied on sources produced outside of the group, which are polemical in nature. This book looks at newly recovered primary texts in order to study the Ghulat first hand. Mushegh Asatryan examines the development of the Ghulat writings, situating the community within a broader historical context and presenting a survey of their distinctive cosmology. Through his detailed analysis, the book provides insight into the formation of an early religious tradition in Islamic history as well as the nature of the community in which these texts were produced and circulated.