Red Secularism is the first substantive investigation into one of the key sources of radicalism in modern German, the subculture that arose at the intersection of secularism and socialism in the late nineteenth-century. It explores the organizations that promoted their humanistic-monistic worldview through popular science and asks how this worldview shaped the biographies of ambitious self-educated workers and early feminists. Todd H. Weir shows how generations of secularist intellectuals staked out leading positions in the Social Democratic Party, but often lost them due to their penchant for dissent. Moving between local and national developments, this book examines the crucial role of red secularism in the political struggles over religion that rocked Germany and fed into the National Socialist dictatorship of 1933. This title is part of the Flip it Open Programme and may also be available Open Access. Check our website Cambridge Core for details.