|There is no question that books have been edited, stripped out, and added over the centuries. As far as the gospels and much of the new testament are concerned, this is incorrect. We get the Jesus narrative from the gospels, and we have really early copies of the gospels, dating back to as early as 125 AD, which, in the case of the Gospel of John is only 30-40 years after the first publication. Considering that it was the old world, pre-printing press, this isn't irregular or uncommon. Also, understand that these writings weren't disposable or thrown around the way we throw books around today. These writings were venerated and cherished. Orthodoxy also holds that tradition is just as valid as the written word. In this case, tradition verifies the text. The Western mind boggles at this, because it has no exposure to (and thus no respect for) any kind of tradition. Anyway, here's a chart with dates: http://en.wikipedia.org/wiki/Dating_the_Bible#The_New_Testam...
Holding tradition as being as valid as a written reproducible document unfortunately does not remove the error introduced to by oral tradition, -especially those errors compounded over several decades. Unfortunately, no oral information set in existence has been able to demonstrate zero corruptibity over an observed period of decades, let alone years. This issue is mitigated somewhat if you accept that the Bible is not the literal word of god, but not entirely. Merely holding something to be so does not make it accurate or valid empirically, especially in opposition do evidence to the contrary. That's the main problem that a skeptic would have with this and it can't be EFFECTIVELY addressed through reason. Observable evidence does not support traditional arguments that some sort of higher respect or reliance on oral tradition magically reduces error rates anywhere near zero. Especially on multiple large stories.Orthodoxy also holds that tradition is just as valid as the written word. In this case, tradition verifies the text.