This book presents the first English translation of the Mäṣḥäfä Mǝsṭir (“Book of Mystery”) of Giyorgis of Sägla. Giyorgis lived in Ethiopia during the late-fourteenth and early-fifteenth centuries and is the earliest-known prose author in the history of not only Ethiopia, but anywhere in Africa south of the Sahara. While he wrote many works, the Mäṣḥäfä Mǝsṭir is his most well-known and influential. The purpose of this monumental work was to educate lay Christians and monks in matters of orthodoxy in order to defend the Christian faith and it was intended for use in church worship. Giyorgis’ Mäṣḥäfä Mǝsṭir is an indispensable resource for studies in theology and history. This volume also includes the first English translation of Giyorgis' biography. This book is also a helpful aid for Christians in theological and devotional formation. This translation is being printed with Rehobot Printers, located in Addis Ababa, and is available now for pre-order.