Is anyone aware of when Puzo set pen to paper to compose his novel? I assume it was post 1963 after Valachi used the term Godfather in his Senate testimony.

As some have stated, Vito was a composite of sorts of several high profile Mafia Dons. However, overall, I believe that Vito was based mostly on Joe Bonanno/Profaci. As we sometimes do on this Board, we mix references from the novel and the film. So will I.

Vito brought Michael into the business as Joe brought Bill into the business; Joe strongly allied himself with Profaci, thus bringing the olive oil business into the mix. Despite Gambino's children, it was Bill's marriage to Profaci's daughter that was the basis for Connie's wedding. Magliocco, succeeding Profaci, moved against some of the Dons thus parallelling Sonny's tried and failed (in the novel) move against the families. Vito took over Maranzalla's empire just as Bonanno took over Maranzano's. The attempted Troutman Street ambush of Bill Bonanno parallel's the attempted ambush of Michael by Barzini. Gaspar DiGregorio's betrayal of Bonanno parallels Tessio's betrayal of Vito.

In any case, that's my analysis.