Honest question: are you familiar with why the books that are in the Bible were chosen, and why the other "gospels" were excluded? And not via a Dan Brown book.
It was a long and adaptive process over the span of a number of centuries. Not all religions have the exact same version of the Bible, either. Their faiths, for whatever reason, chose differently at different times.
The exact reasons why some were chosen, and others were not, are in many cases now lost to time. Others are recorded in church records.
In all cases, however, what we now call the Bible was chosen by men, based on their own belief systems and interpretations of how the various liturgical texts were relevant in their lives and in the lives of the members of their community.
This site discusses the selection process:
http://www.biblica.com/bibles/faq/7/I find this passage to be particularly interesting...
" Some of the churches were using books and letters in their services that were definitely spurious. Gradually the need to have a definite list of the inspired Scriptures became apparent. Heretical movements were rising, each one choosing its own selected Scriptures, including such documents as the Gospel of Thomas, the Shepherd of Hermas, the Apocalypse of Peter, and the Epistle of Barnabas.
Gradually it became clear which works were truly genuine and which mixed truth with fantasy. By the end of the fourth century the canon was definitively settled and accepted."
Uhm... OK. I find that to be a particularly... interesting... statement.