 After he decided to make the film, Al Pacino (qv) invited  Frank Serpico (qv) to stay with him at a house that Pacino had  rented in Montauk, New York. When Pacino asked Serpico, "Why did you  do it?" Serpico replied, "Well, Al, I dont know. I guess I would  have to say it would be because... if I didnt, who would I be when  I listened to a piece of music?"