What would it take?

[JackRussell]

Books aren't evidence.

They are evidence of having been written by someone at some time. They can be dated (using various techniques) to identify linguistic changes over time, support archaeological findings, and give insight into the culture and practices of the time, etc.

I admit to being somewhat hyperbolic.

I agree with your assessment; books are not necessarily good evidence, otherwise we would believe everything written. Books need to be carefully assessed and require further supporting evidence to back them up. The evidential claims within any book do require further scrutiny though; talking snakes, night flights to Jerusalem, golden plates in North America and Julius Caesar seen as a dimi-god arising as an eagle.

Paleo-linguistics, archaeology and anthropology can certainly shed some insights; I don't know how any of that gets us any closer to verifying supernatural events though, seems a little slim to me.