A tireless organizer, speaker and writer who helped found International Women’s Day, German revolutionary Clara Zetkin devoted her life to building the revolutionary socialist tradition worldwide. This talk is an introduction to her contributions, including a Marxist analysis of women’s oppression, the fight against reformism within the German socialist movement and the struggle to build opposition to the First World War. A selection of Zetkin’s writings—Clara Zetkin: Selected Writings—has recently become available through Haymarket Books.