Athanasius is the first person to identify the same 27 books of the New Testament that are in use today. Up until then, various similar lists of works to be read in churches were in use. Athanasius compiled the list to resolve questions about such texts as The Epistle of Barnabas. Athanasius includes the Book of Baruch and the Letter of Jeremiah and places the Book of Esther among the "7 books not in the canon but to be read" along with the Wisdom of Solomon, Sirach (Ecclesiasticus), Judith, Tobit, the Didache, and the Shepherd of Hermas.
How many books are in the New Testament?
27 books