The novel, while crudely written compared with the polish of the film, did have many interesting and useful details and side stories that didn't appear in the film. The best were: the Bocchicchio Family and how they helped Michael return from Sicily; Neri's background and recruitment; Sonny and the boiler inspectors; Vito's war with Maranzano. I could have done without all that Lucy/Jules crap (a flimsy vehicle for Puzo to describe her gynecological operation); all of Nino, and nearly all of Johnny following Connie's wedding. Most of that was Puzo's way of showing off what he learned about Hollywood. That Hollywood BS ruined "The Last Don."