Who wrote/compiled/edited (and when) the various New Testament Books?
Tradition has assigned the Gospels and most of the Epistles to certain authors, all of whom were important figures in Jesus' life or the early days of the faith. The first generation of Christians didn't see any need for a permanent written record of Jesus. Accounts were simply passed along orally, primarily as a means of preaching and convincing outsiders. But as the first generation began to die off, there was a need to preserve Jesus' words and deeds for posterity.

Mark is regarded as the earliest gospel. Mark, not an apostle himself, was an associate of the apostle Paul for a short time, but the gospel bearing his name is (to some minds) based on the preaching of Peter. It's generally assumed to have been the first gospel written, coming in right before Matthew at about 65 AD. The author of Matthew is traditionally held to be the tax collector mentioned in Matthew 9:9, sometimes referred to as Levi. Matthew borrows heavily from the Gospel of Mark. Since this gospel has the most quotations from the Old Testament, sometimes going to lengths to try to show that Jesus was the fulfillment of Old Testament prophecy, it's assumed that Matthew was written for a Jewish audience. It might have been originally written in Hebrew, although only Greek texts have ever been found.

The Gospel of Luke and the Book of Acts are assumed to have been written by the same person, since they are addressed to the same individual, a Roman named Theophilus. The author was a doctor, Paul notes in Colossians 4:14. If Mark represents the teachings of Peter about Jesus, Luke most likely represents the teachings of Paul.

The book of Acts can be seen as a sequel to the Gospel of Luke, starting where the previous book ends. But where in the earlier work Luke needed to research the story, in Acts he is a character in it. He was a companion of Paul on his missionary journeys and was present during his imprisonment. In this sense, Luke had more first-hand experience of Paul than he had of Jesus. Both books were probably written after Matthew and Mark, probably around 65-70 AD but before the destruction of Jerusalem in 70 AD.

The Gospel of John differs markedly from the other three books both in tone and in some historical details. John does not follow the timeline in the other three and adds quite a few stories and details not found in them. The three letters of John found near the end of the New Testament are generally assumed to have been written by this same individual. Tradition has it that John is "the disciple that Jesus loved" mentioned in John 13:23.
The letters to the Romans, the Corinthians, the Galatians, the Ephesians, the Philippians, the Colossians, the Thessalonians, Timothy, Titus and Philemon are from the apostle Paul and are called the Pauline epistles for that reason.

The author of the letter to the Hebrews is completely unknown although Barnabas (an associate of Paul), Apollos, or even a dual authorship of Aquilla and Priscilla, two Christians who ran a church out of their house in Rome have been suggested.

The letter of James isn't anonymous. But five people named James are mentioned in the New Testament, one of whom was the brother of Jesus. It's this person whom tradition has accepted as the author.

The book of Revelation is credited to John and most critics put the date at about 95 - 100 AD.

Written by The Straight Dope Staff Members Dex and Eutychus.