I accidentally ran across an excellent lecture given just last week:
"The Four Gospels and the Other Gospels: Is Our Canon Right?"
by Richard Bauckham
If you're wondering why we have Four Gospels in our Bibles, and why none of the 'other gospels' that have been so widely talked about weren't included, don't miss this lecture (48 minutes). This is the best lecture I've ever heard on it!excerpted from link:
On November 14, 2007, the Westminster Students Association (WSA) had the honor of inviting one of the world's leading New Testament scholars, Dr. Richard Bauckham (Ph.D., Professor of New Testament at the University of St. Andrews) to give a free lecture entitled "The Four Gospels and the Other Gospels: Is Our Canon Right?" in the WSC Chapel.
Dr. Bauckham is author of Jesus and the Eyewitnesses (Eerdmans, 2006), winner of the Christianity Today Book Award for Biblical Studies in 2007.
Among other things Bauckham talks about is: that the 'other gospels' were written later than the Four Canonicals and, therefore didn't have apostolicity (meaning they weren't old enough to genuinely have apostolic authority or "be the real deal" so to speak) . He uses 'other gospels' content to prove it.
In the past most scholars thought the early Christians were forced to decide what books to put in the Bible due to the pressure from gnostics and other groups or individuals, like Marcion. Baukham says he doesn't think the early Christians really had this pressure as far as the Four Gospels go. In other words, the Four had been accepted for a long time by then. Well...um, he can explain it better than I can,
This is really good stuff. Simple and basic yet covers the details.
Rick