My Opposition (German: Mein Widerstand) is a diary secretly written by the German social democrat Friedrich Kellner (1885–1970) during World War II to describe life under Nazi Germany and to expose the propaganda and the crimes of the Nazi dictatorship. Comprising ten notebooks, it is considered by leading historians as "an important piece of historical literature." The editors of the German magazine Der Spiegel called it "an image of Nazi Germany that has never existed before in such a vivid, concise and challenging form." Kellner began his 861-page diary on September 1, 1939, and wrote his last entry on May 17, 1945. In 1968 he gave the diary to his American grandson, Robert Scott Kellner, to translate into English and to bring it to the attention of the public.