This monograph explores the religious and cultural transformation of Sogd, a key region situated along the Great Silk Road. Drawing on archaeological findings, written sources, and iconographic materials, it traces the historical development and interaction of four major religions: Buddhism, Manichaeism, Christianity, and Islam. The study highlights how these religions shaped the social and spiritual life of Sogdian society, the mechanisms of their dissemination, and the mutual influences they exerted on one another. Special attention is given to the unique synthesis of religious beliefs, cultural tolerance, and the role of Sogdian intermediaries in transmitting religious ideas to China and beyond. The work provides new insights into the religious dynamics of Central Asia from antiquity through the early Islamic period.