According to the official press release :

"At the time of his death in 1999, though he had reached the end of the story-including writing the epilogue-Puzo had left several chapters unfinished. Working directly from his detailed notes and outline, his longtime companion, novelist Carol Gino, completed the work soon thereafter."

The book contains 30 chapters.

Carol will be coming on here soon to talk about the book, so maybe you can get a more clearer answer then...

JG