This book studies the 18th-century Jerrahi religious order from Istanbul, renowned for its composers and musicians, and their contribution to the development of religious music. Along with the history of the order, the author examines the relationship between mysticism, literature, and music. He studies the dhikr, rituals, and other worship performed from a musical perspective. The author follows the path of the order and its music, and reveals its transformation and continuity in the modern era when the religious orders were closed in the Turkish Republic. The final section focuses on the biographies of the composers and provides details about their work.