screenwriter

Mario Puzo, the author of The Godfather books who helped adapt them to film, had no formal training and had never written a screenplay before. After winning two Oscars for the first two movies, he decided to buy a book to help him learn to how to screenwrite. – WTF Fun Facts

Source: https://www.npr.org/2019/03/08/701492922/a-look-back-at-the-godfather-with-mario-puzo-and-francis-ford-coppola