Lesson 3 - Hitler's foreign policy
The important long-term structural problems caused by the First World War and the failure of the international system of peacekeeping embodied by the League of Nations, can only partly explain the outbreak of war in 1939. As always in history, the actions of human participants (human agency) must always be considered a part of the explanation. In the case of the Second World War, the actions of one man in particular were particularly important, Adolf Hitler.
John D Clare has an alternative eight steps to war - https://www.johndclare.net/RoadtoWWII3.htm
1. German armed forces to be limited - pp.258-9
2. Demilitarized Rhineland - pp.260-1
3. Anschluss Forbidden - p.263
4. The Sudetenland - p.266-7
5. The Polish Corridor - p.271-2