A monumental study by the distinguished academic and Greek scholar, founder of the "Sources Chretiennes" series, which refers to the early Christian period and the doctrinal and liturgical development of the first Christian communities amidst Jewish messianic movements, some of which accepted Jesus, and diverse Gnostic schools. The researcher examines the discovered hidden literature of the time in Qumran and Nag Hammadi in parallel with the Christian literature of the 1st century and the beginning of the 2nd century, highlighting the common theoretical background of Semitic origins, part of which was adopted by the early Christians. The matrix of these spiritual fermentations was Jerusalem and the wider region of Palestine, and the recipient and carrier of the Judeo-Christian influences initially was the Mother Church of Jerusalem and its shepherd, Brother Theodosius James. It is a work-tool in the field of History of Doctrines, as it helps the reader familiarize themselves with the spiritual environment of the New Testament era and explain some hitherto misunderstood aspects of doctrine.