I thought the tale of this family was one of the best back stories in the novel, and I was also very sorry that it didn't make it into the movie. And when Puzo tied it all together to have Vito find a way to bring Michael home, that was perfect.
I agree 100 percent, SB! Although the novel wasn't a great literary work, Puzo shared in the great Italian storytelling tradition--and the story of the Bocchicchio's and their special niche in American Mobdom was a great story. Puzo told it in an ingenious and compressed way. The Bocchicchio's and their role in rescuing Michael stands alongside Neri's background and recruitment as the two best (as you put it) backstories from the novel that would have enhanced the movie.
