21
The 6 books of the New Testament that are not letters include: Matthew, Mark, Luke, John, Acts, and Revelation.
There are no books called "letters" (or epistles) in the Hebrew Old Testament. All books that are designated as "letters" are Greek, and found in the New Testament.
There are books in the Old Testament, letters are in the New Testament.
Historical, letters, and prophetic books.
Letters
If by 'works' you mean writings such as books or letters, then there are 27 in all.
There are a total of 27 books in the New Testament
There are 27 books in the New Testament.
There are 39 books in the Old Testament and 27 in the New Testament.
All that are not the Four Gospels, Acts, and Revelation.
It is the letters by Paul.
There are 21 letters written in the New Testament. Romans to Jude