This work was especially used by the Albigenses, a medieval Christian group. Many people believed it came from the Bogomils, who lived before them. The book is written as a conversation in which the apostle John asks Jesus questions and receives answers while sitting close to him during the Last Supper. This question-and-answer style also appears in other early Gnostic writings, such as the Gospel of Bartholomew.
The book includes Gnostic beliefs. It says that Satan, not God, created the world. It teaches that Christ was not born of Mary in a human way. Instead, Christ was an angel sent from heaven. He "entered by the ear and came forth by the ear" of Mary. The book also claims that Satan sent John the Baptist and that his followers (identified with the Roman Catholic Church) are not the disciples of Christ. It further teaches that baptism and the Lord’s Supper have no real value.
This writing survives only in Latin. The version we have today dates from the twelfth century or later. An English translation can be found in The Apocryphal New Testament (1924) by M. R. James.