In his diary, with entries spanning from May 1936 until his arrest in October 1944, Friedrich Reck-Malleczewen sharply critiques the barbarism of National Socialism, foreseeing the inevitable collapse of the regime. Reck-Malleczewen's text, first published in 1947, became his most renowned work and one of the most significant documents of the Hitler era. The diary has been translated into French, Dutch, English, Italian, and Spanish.

Friedrich Reck-Malleczewen (1884–1945) was a German writer and journalist. In 1944, he was interned in the Dachau concentration camp, where he perished in February 1945.