The process of canonization of the biblical text or the Bible that we have now, is long and complex.
Most people think that the 66 books that comprise the Bible have been set in stone and that they are a settled (and eternal) issue, but it really depends in most part what Christian tradition or denomination you’re affiliated with.
I can only imagine how (radically) different Christianity would have been like if such books were included and other current ones, like the Book of Revelation, had been omitted.
Very interesting article about a new book coming out soon.
http://articles.philly.com/2013-03-04/news/37412901_1_christianity-new-testament-bible-scholars
Project Augustine 
I found that book called “A New New Testament” fascinating, particularly the Secret Revelation of John. But I found it interesting as showing how ideas develop: it was wrong in an interesting way.