James Patrick Cannon (February 11, 1890 – August 21, 1974) was an American Trotskyist and a leader of the Socialist Workers Party. Born on February 11, 1890, in Rosedale, Kansas, the son of Irish immigrants with strong socialist convictions, he joined the Socialist Party of America (SPA) in 1908 and the Industrial Workers of the World (IWW) in 1911. He was personally trained by "Big Bill" Haywood, a top IWW leader, and was an IWW organizer throughout the Midwest from 1912-14.