Books that made it into the canon.?

I've read very old findings of mary Magdalene's gospel, the accounts of revelations from john and peter, and a whole other book that was supposed to occur before the flood. now we all know that a bunch of bishops or leaders of the roman catholic church got together to decide what books would be in the "canon", or New Testament...my question is what was there reason for casting aside the "Lost Scriptures"., and is it possible for books outside the bible to be divinely inspired?