It's set 1933-1934 mostly. Frankie Pentangelli and Genco are both part of the story, as are Clemenza, Tessio, Luca Brasi, The Rosato brother, The Barzinis, and lots of other characters from the original books and movies--and then there's a whole other crew of Irish gangsters that are part of the story, too. Vito's there, too. One of the early reviews said the depiction of Vito was especially good.