I read part one of The Godfather, but decided to abandon the rest of the book. The movie portrays the book really well, in fact almost exactly. The dialogue is nearly word for word. I think it is a testament to how well both are crafted. This leads me to wonder, why am I even reading the book if I get nothing new out of it? So I decided to move on.
Extra credit: Why The Godfather Is the Best Depiction of Masculinity