John Riddell has been active in the revolutionary socialist movement in Canada, the United States, and Europe since the 1960s. He is a socialist historian and editor of a series of books on the Communist International in Lenin's time, including Toward the United Front: Proceedings of the Fourth Congress of the Communist International, 1922 (Haymarket Books, 2012). He is a frequent contributor to the ISR on the history of the revolutionary socialist movement. His writings past and present can be found at his blog, John Riddell: Marxist Essays and Commentary.