Why do you believe the Scriptures are truly inspired by God? Why not the books that haven't been canonized?
I actually believe there are other books other than the 66 books in the bible. I believe God had a hand in the 66 books that were chosen. I believe He knew we would need those books. It's impossible to put in a single book everything Jesus did, much less the events following Adam and Eve.
However, I believe not all the books outside the bible are of God, but the enemy. I don't know which are good or bad, but I have to research and pray about it.