»The First World War - a defensive war?«: The First World War was the most extensive war in history to date. What were the causes of this war? In the official account of the German government, Germany was engaged in a defensive war. The author questions this account and discusses the role of influential forces in the empire that may have pursued annexationist war aims with the war. Similarly, the significance of World War I for subsequent events in 20th century history is examined. In what ways did it shape the anti-semitic ideology of National Socialism? Was National Socialism also a result of the First World War? What lines of connection can be drawn to the Second World War?