In the first years of World War II, Chief Corporal Felix Hartlaub served in a barrage battalion in the Ruhr region. During the occupation of Paris, he worked in the archives commission for foreign affairs, and then ended up at Hitler's headquarters. Here, in a secret zone protected from the whole world, Hartlaub kept an official journal of military operations and secretly in his diary recorded personal observations of the daily life of the Fuhrer's main headquarters. His testimony provides an opportunity to look at events from an unexpected perspective, presenting a picture of the conduct of a total war from Hitler's secret headquarters. In May 1945, when keeping a combat log lost any meaning, the chief corporal was sent to an infantry regiment to participate in the battles for Berlin, but went missing on the way to his destination. In 1955, the diary was published by the author's family.