Thirteen epistles (
Romans, 1 Corinthians, 2 Corinthians, Galatians, Ephesians, Philippians, Colossians, 1 Thessalonians, 2 Thessalonians, 1 Timothy, 2 Timothy, Titus and
Philemon) are attributed to Paul, one to James, two to Peter, three to John and one to Jude. The Epistle to Hebrews was also at one stage attributed to Paul, but this is too clearly not the case.
The consensus of scholars is that only
Romans, 1 Corinthians, 2 Corinthians, Philemon, Galatians, Philippians and
1 Thessalonians were really written by Paul, and that the remainder were written in Paul's name after his death. A.Q. Morton goes further, having carried out a computer analysis of the epistles attributed to Paul and found that only
Romans, 1 Corinthians, 2 Corinthians and
Philemon contain exactly the same writing style as Galatians.
Scholars doubt the authenticity of the epistles attributed to James, Peter, John and Jude. For example,
Jude clearly identifies itself as a second-century work, even though it also claims authorship by
Jude.
2 Peter must have been written even later than
Jude, since it incorporates almost all of the text from
Jude. So apart from the five or seven epistles by Paul, we do not know who actually wrote the epistles in the New Testament.