What's the significance of the books Alfonso found?
Again, the books that Alfonso finds in Prairie's bedroom are one of the most significant aspects of the finale, and it's worth taking a closer look at the discovery. Of the four books, only two are real: The Iliad by Homer (duh!) and The Oligarchs by David E. Hoffman. The other two, the Encyclopedia of Near Death Experiences and The Book of Angels by Audrey Ebbs, are fictional titles created for the show. (However, as one Reddit sleuth points out, Audrey Ebbs is the name of a real singer/songwriter who has written a novel about a character named... wait for it... Buck.)
After Alfonso finds the books, he jumps to the conclusion that Prairie must have been consulting them for references to weave into her tale of captivity. That's an odd conclusion to make, though: given Prairie's past, would it be so out of the question that she'd seek out books about topics related to her life? She grew up in Russia, so why not read a book about Russia? She had a near-death experience -- and was kidnapped by a man who performed near-death experiments on her -- so, why not brush up on some medical history? From a plot perspective, I get why Alfonso questioned Prairie, but I'm not sure the books are the smoking gun the creators intended them to be.