Update:
I've been steadily working on translating/transcribing the text from the books aaaaand the book at the very beginning translates to this:
"Warning!
All of these books are my (delusions) cheap ideas.
...Or should I say dreams. They seem like explanations.
At the very least they’re my individual interpretations and cheap ideas that I came up with.
Again, most of the books are written horizontally. Reading vertically gives you a pretty much unknown meaning.
Well then… Have fun!"
Damn it! Just when I was hoping for some actual Urotsuki narrative... Aughhhh.