Sidney Lens (1912–1986) was a socialist, labor and antiwar activist, and author. He wrote many books, including a history of U.S. intervention abroad, The Forging of the American Empire, originally published in 1974 and republished in 2003 by Haymarket Books with a new introduction by Howard Zinn; an autobiography; Unrepentant Radical; and Labor Wars, also republished, in 2009, by Haymarket.