Well, I've read every Mario Puzo book, I'm not sure who else has. Anyway, I'll give my opinion on them with a full ranking. Rememberr, these are only my opinions, and not for the BEST book, but my FAVORITE. Some were hard to rank.
7.Dark Arena
6.Fortunate Pilgrim
5.Last Don
4.
3.Omerta
2.Godfather
1.Fourth K

Alright, a few things. Now, these are my favorites, and Fourth K is number 1. Not a mob book, way out of his genre, but I've said it before...I love this book. Thing is, I had Godfather there at one point, but I thought about it and realized that Godfather was ruined for me due to the fact that I had seen the film first. Had I read and then watched, it would be 1, but thats how it went. I did watch the film after and feel the book truly compliments the film and vice versa. Omerta is number 3 because it was the first Puzo I read and the one that pulled me in the most. I went back and forth between Sicilian and Last Don, but put Sicilian ahead for the story and ending. I guess Last Don was TOO contemporary. Then I put Fortunate Pilgrim, and that was hard, because it was the most detailed, most literary, but not one of my favorite. Dark Arena is last, and while ok, I've said before, its just not amoungst my true favorites. Now just to read Family and see where that fits in. I know we've done rankings before, but anyone read all the books and are able to rank all of them?