Greenleaf proceeds to argue that "In matters of public and general interest, all persons must be presumed to be conversant, on the principle that individuals are presumed to be conversant with their own affairs" (p. 9). On the basis of this legal rule, Greenleaf briefly profiles those traditionally attributed as authors of the Four Gospels, Matthew, Mark, Luke and John, concerning (in the case of John and Matthew) their firsthand knowledge of the life of Jesus of Nazareth and (in the case of Mark and Luke) their intimate personal links with Jesus' original band of disciples.