When looking at the historical reliability of the Bible, I’ll first concentrate on the Gospels since the accounts of the life of Jesus are the linchpin of the Christian faith. Falsify that, and everything else falls apart as well. Confirm the historicity of the gospels, and you cannot avoid the truth claims of the faith.
There are many attacks against the historicity of the gospels. The most popular today include the assertions that the gospels are a bunch of stories made up to deify a man who may or may not have actually lived in order to advance some nefarious agenda, that the gospels were written in order to solidify the political power of Constantine, or that the gospels are nothing more than a retelling of other savior myths. There are many others, but the vast majority of them depend upon an easily disprovable premise: that the gospels originate hundreds of years after the time that Jesus lived.
If it can be shown that it is reasonable to conclude that the gospel narratives originate early enough that they could have been easily disproven by eyewitnesses to the events, then these ‘late date’ based arguments are falsified, and the gospels must be taken as at least as accurate as other contemporary histories.