I recently listened to an audiobook of The Godfather by Mario Puzo. Check it out on Librarything here. Of course I have seen the movie many times on TV. I first read the book back in the 1970's, when I was just starting high school.
The story holds up very well. The actions of the Corleone clan and the story of how Michael became the new Don is still gripping and well told. Still, the language is typical of the late 60's and doesn't accommodate today's sensitivities.
The Hollywood part of the story is mystifying. It could have easily been shortened or left out without hurting the story. What did Puzo include it?
I was fascinated by the Mafia philosophy. This came out in different parts of the story, when Michael was in Sicily and in the recounting of how his father turned to crime in his youth. The story showed how he learned that he couldn't rely on society to create a safe environment. Instead, he had to create his own world with its own rules. Intimidation and violence was okay if it was to protect his people and family. Loyalty was everything.
The justification for having guns reminded me of some of the more extreme justifications of gun advocates. They claim that we can't rely on society to protect us. They say we should be armed and ready for violence at all times.
The book ended differently from the movie. In the book, Michael's wife, Kay, converts to Catholicism and attends daily Mass to pray for the soul of her husband. I think this was a better ending, although it didn't allow for sequels.