I had to guess at what "book of john" was, and i went with the obscure answer :)

There's the gospel according to john, which is the fourth, and non-synoptic, canonical gospel. It's what you get when you take a Hebraic metaphysical worldview and try your damned best to cram it into the heads of hellenestic (neo)platonists, which accounts for the whole Logos thing, etc. And even when trying to speak neoplatonist, the author(s) of john can't resist falling back on revelatory rhetoric.

There's the revelation to john, which i, at least, (as a preterist) think is a survival guide to not getting crucified more than anything else.

and then there's https://en.wikipedia.org/wiki/Mandaean_Book_of_John , which i don't know anything about at all. If it does structure itself like a proof, i'd be very surprised.