Harry Grey's 'The Hoods' was first published in 1952. He had been involved in organised crime and much of the book is based on his experiences. Grey also wrote a biography of gangster Dutch Schultz which was made into the film Portrait of a Mobster.

Leonardo Benvenuti and Piero De Bernardi were a screenwriting team who had collaborated many times before working on Once Upon A Time In America. Together they wrote over one hundred screenplays, winning several awards, before Benvenuti died in 2000.

(Benvenuti, left; De Bernardi, right)

Enrico Medioli was a screenwriter for many of director Luchino Visconti's films, including Rocco and his Brothers, The Leopard, and The Damned. He has continued to write for film and television, including adapting Tolstoy's War and Peace for a forthcoming television miniseries.

Franco Arcalli was a screenwriter and film editor for many of director Bernardo Bertolucci's films, including The Conformist, Last Tango in Paris, and Novecento. He also edited the Michelangelo Antonioni films Zabriskie Point and The Passenger. Arcalli died in 1978.

Franco Ferrini was a young film critic and great admirer of the films of Sergio Leone when the director asked him to contribute to the script for Once Upon A Time In America in the 1970s. He has since written many Italian films and television miniseries, including several for horror movie director Dario Argento.

Stuart Kaminsky is the author of many crime novels and short stories. He also writes articles for cinema journals and has written four film biographies.