[Suzerain of Sheol]

4. The Princess Bride: S. Morganstern's Classic Tale of True Love and High Adventure, by William Goldman

If you've only seen the movie, you don't even know half the story. It's hard to really say which version is better -- Goldman wrote both, and he's a screenwriter by trade, the movie is a simple and complete, while the book is dizzying and leaves nothing but questions.

Don't get me wrong, the entire charming plot of the movie is there in the book, just like you remembered it, but there's also a frame of postmodern meta-fictional boon-within-a-book-within-a-book going on... and no, S. Morganstern never existed.

Regardless! One should read it just for experience, there's really nothing else like it, at least that I've come across.