St. John of Damascus (John Damascene) is the author of the "Exact Exposition of the Orthodox Faith" ("On the Orthodox Faith"), included in this volume. Standing among the greatest of the early Church fathers of the East during the patristic age, he produced his work The Fount of Knowledge as a summary of Christian philosophy and theology. Encompassing “The Philosophical Chapters,” “On Heresies,” and the justly-famous “Exact Exposition of the Orthodox Faith,” it is one of the most important works of the Greek patristic age—a veritable Summa of the doctrine of the Eastern fathers. This Ex Fontibus edition reprints the excellent twentieth-century translation by patristics scholars who contributed to a series published by Catholic University of America press. (Ex Fontibus Co.)