In 1984, George Gipe was contracted to write the novelization of the movie Back To The Future. He was supplied with a screenplay still in flux, writing his novelization even as the movie itself was being rewritten and as major roles were being recast (Michael J. Fox was not the first person to play Marty McFly). Partially because of this, and partially because of Gipe's natural writing style, the novelization is coo-coo bananas. It is totally insane. It's... kind of awesome?
I feel like I should mention that after he submitted his manuscript, George Gipe was stung to death by bees.
This book is the page-by-page reading guide to Gipe's novelization of Back to the Future, pointing out where things are different from the movie (often!) why and how they're worse (even more often!) and even when they're better (it happens, like, twice). It is written by Ryan North who writes the online strip Dinosaur Comics and the Adventure Time comic book. There are lots of pictures and lots of jokes and you will have a fun time reading (EVEN MORE SO THAN YOU NORMALLY DO).
A copy of "Steven Spielberg Presents: Back To The Future: A Robert Zemeckis Film: The Novel by George Gipe based on a screenplay by Robert Zemeckis and Bob Gale" is totally not required to enjoy this book!