Clifford Irving wrote a "historical fiction" novel, "Tom Mix and Pancho Villa", about Mix's involvement with Mexican revolutionary Pancho Villa and his supposedly joining Villa's army in the fight against dictator Porfirio Díaz in the bloody Mexican civil wars of the early 20th century. While it's known that Mix did spend time in Mexico during that violent era and had mentioned years later that he had in fact met Villa, it's not known if their association was as close as Irving claimed it was in the novel.
