Alfredo Jose de Arana-Marini Coppel was an American author. He served as a fighter pilot in the United States Army Air Forces during World War II. After his discharge, he started his career as a writer. He became one of the most prolific pulp authors of the 1950s and 1960s, adopting the pseudonyms Robert Cham Gilman and A.C. Marin and writing for a variety of pulp magazines and later "slick" publishers. Though writing in a variety of genres, including action thrillers, he is known for his science fiction stories which comprise both short stories and novels.