Book excerpt: The German social democratic movement was the first mass, working-class party in world history, and a prototype for one of the major features of twentieth-century politics. Gary P. Steenson presents an introduction to the origins and development of German social democracy up to the First World War, by drawing upon protocols of the German Social Democratic Party, the party press, correspondence of leading figures, and scholarly research. Steenson also offers biographical sketches of prominent party officials, and translations of party programs and bylaws in the appendix.