This is the first fully researched biography of Martin Niemoller (1892-1984). It charts his life from his service in the Imperial German Navy, his work for the Inner Mission and as a Protestant pastor in the Berlin suburb of Dahlem from 1931. Niemoller’s work as a leading figure of the Confessing Church and his contribution to the conflicts over church policy during the Third Reich are analysed and contextualised. Chapters on the post-war period chart Niemoller’s contribution to ecumenism, anti-nuclear pacifism, and his role in rebuilding the West German Protestant Churches. From 1938 to 1945, Martin Niemoller was detained as ‘Hitler’s Personal Prisoner’ in Nazi concentration camps. Liberated in April 1945, Niemoller was widely hailed as an icon of Christian resistance against the Nazi dictatorship. For many years, the Niemoller legend masked the problematic aspects of his life: his persistent antisemitism, on display even in the post-war period; his nationalism and support of the German war effort even whilst in concentration camp detention; and his disdain for parliamentary democracy. In his biography of the most important twentieth-century German Protestant, Benjamin Ziemann uncovers the ‘historical’ Niemoller behind the legend of the resistance hero. Carefully situating Niemoller’s personal trajectory in his wider social milieu — from the Imperial Navy to the West German peace movement — Ziemann probes into core themes of twentieth century German history: militarism, National Socialism, German guilt, and moral reconstruction post-1945.