novel  by Mario Puzo . With a  screenplay  by Puzo, Coppola and an uncredited  Robert Towne , the film stars  Marlon Brando ,  Al Pacino ,  James Caan ,  Robert Duvall ,  Sterling Hayden ,  John Marley ,  Richard Conte  and  Diane Keaton , and features  John Cazale ,  Talia Shire , and