This book is based on Florovsky's lectures given at the Institute of Orthodox Theology in Paris from 1928 to 1931. It was inspired by the conviction that books in Russian on the Fathers of the Church were badly needed, not only by theological students, but also by a much wider circle of those concerned with doctrinal and spiritual vistas and issues of Eastern Orthodox Tradition. Revisions have been made for this English edition. The author says that this is a history of Christian doctrine, and a kind of Christian philosophy: "Based on an independent study of primary sources, these works may still be useful to both students and scholars." George Florovsky has been called the greatest Orthodox theologian of the 20th Century. This is his overview of the early church and its thought.