Emmi Bonhoeffer was born Emilie Delbrück in the suburb of Grunewald, Berlin, Germany. Her father Hans Delbrück was a well-known military historian who served as a member of the German Parliament (Reichstag), and the center of a circle of intellectuals. Her younger brother was the biophysicist Max Delbrück. The family contained many prominent Prussian administrators, scholars, and pastors. The Bonhoeffer family were neighbors and close friends. In 1930, Emmi married Klaus Bonhoeffer, a lawyer and chief legal counsel to Lufthansa Airlines, with whom she had three children. Klaus was a leader of the anti-Nazi resistance along with his siblings Dietrich and Christel, his brother-in-law Hans von Dohnanyi, and Emmi's older brother Justus Delbrück and cousin Ernst von Harnack. She assisted in their resistance activities. Her husband was arrested after the July 20, 1944 Plot to assassinate Hitler and was executed by the Nazis in 1945, near the close of World War II. Emmi fled Allied bombing with her children to Schleswig-Holstein and after the war became involved in various humanitarian and social efforts and anti-Nazi educational work. She took part in the acclaimed British documentary series The World At War (1973-74). She also wrote Auschwitz Trials: Letters from an Eyewitness (1967).