Includes bibliographical references and index.

Karamustafa bases this study on a fresh reading of the primary sources and, by integrating the findings of recent scholarship on the subject, presents a unified narrative of Sufism's historical development. His innovative analytical framework reveals the emergence of mystical currents in Islam during the ninth century and traces the rapid spread of Iraq-based Sufism to other regions of the Islamic world, providing an integrated, comprehensive understanding of one of the most compelling aspects of late antique, early medieval Islamic religious history.--From publisher description.