Harold MacGrath (September 4, 1871 - October 30, 1932) was a bestselling and prolific American novelist, short story writer, and screenwriter. He sometimes completed more than one novel per year for the mass market, covering romance, spies, mystery, and adventure. He was the first nationally known writer to be commissioned to write original screenplays for the new film industry. In addition, he had eighteen novels and three short stories adapted as films, in some cases more than once. Three of these novels were also adapted as plays that were produced on Broadway in New York City. MacGrath traveled extensively but was always based in Syracuse, New York, where he was born and raised.