Why does the Protestant Bible have 66 books and the Catholic Bible have 73?
The extra books in the Roman Catholic Bible are from the Apocrypha. The apocryphal books were not considered to be inspired and thus were not recognized by the church as part of the Bible. At the Council of Trent (A.D. 1546) the Roman Catholic Church included them in their Bible.
For more information on this, you can read the study on Bibliology: The Doctrine of the Written Word on our web site.
Related Topics: Canon