With a new introduction by David Malick, The Catholicos of the East and His People describes the life and customs, both ancient and modern, of the modern Assyrians (“Nestorians”) who formed in the nineteenth century a remarkable outpost of Christianity in the Middle East. The authors, who worked as part of the Archbishop of Canterbury’s Assyrian Mission, enrich the book by giving details of the liturgical services and rituals of the Church of the East, with English translations. They rely in their descriptions on the Sunhadus, or Book of Canon Law, which governs that Church even today.