I read it a long time ago. What sticks out in my mind in the novel the most was the plot involving Lucy Mancini (she is the woman we see Sonny porking upstairs at Connies Wedding.

In the book she is his mistress and it goes on in detail how Sonny has a big dong and only she can take it all because she has a large vagina (yeah I know, weird that this was what was written on some of the pages) she even goes to get surgery to get that corrected. She is a major character in the book

Oh another thing is we get more of Luca Brasi's backstory in the book, more of Al Neeri's backstory, More of the corrupt police cop that beat up Michael.

The book goes into detail about how Paulie goes and beats up the guys that raped Bonasera's daughter.

IMO if you are a fan of the movie, the book is enjoyable but not great.

I read it many years ago and thought it was, while certainly readable, a real potboiler. Quite trashy - I have no interest in revisiting it.

THe first half of the book (up to the restaurant shootings) reads as well as the first half of the film plays. The remainder of the book is undisciplined and overwritten, much too much Vegas. I thin kCoppola was a genius in how he shaped the second half of the film, especially with the crosscutting between the Michael/Sicily story and the Sonny/Carlo story.