James D. Horan was a prolific writer, a New York newspaperman who also penned history, historical fiction and novels (more than 40 books total). He even helped win a Pulitzer Prize for reporting in 1944.
Many of his books were on the Old West, biographies and sketches. His 1954 effort Pictorial History of the Wild West is a classic, especially for the treasure-trove of photos of outlaws, lawmen, gunfighters and more. Horan got some facts wrong. But the book helped revive interest in the Wild Bunch, especially how Butch and Sundance died in South America.