Shirer arrived in Germany dominated by the Nazis and already preparing itself for confrontation with the rest of Europe. He would be an eyewitness to the major historical events leading up to the Second World War. He attended the great Nuremberg rallies and the Berlin Olympics of 1936. He witnessed the build-up of the armed forces that enabled Hitler to take action around Germany's borders: the reoccupation of the Rhineland, the annexation of Austria, the occupation of the Czech Sudetenland the occupation of Bohemia and Moravia. In 1938 and '39, he reported on Hitler's meetings with British PM Neville Chamberlain and the crucial Hitler-Stalin Pact, which allowed for the attack on Poland that heralded the start of the Second World War.
After the attack on Poland he watched Sitzkreig---the Phony War---become Blitzkrieg---the lightening war---as in turn Norway, Holland, Belgium, and France all fell. Shirer described for the American public the French signing of the German terms of surrender on June 21, 1940, in the carriage at Compeigne, the same location where the Armistice to end World War I was signed in November of 1918.
Shirer's diary is more than just a catalogue of political and military events: it's a thought provoking analysis by an intelligent observer of how a country can be taken over by madmen. Shirer's experiences in Germany enabled him to later write the definitive history of the Nazis, The Rise and Fall of the Third Reich.