Mass statelessness emerged as a global phenomenon after the First World War, which broke the surviving dynastic empires of Europe and the Middle East and replaced them with nation-states. This course investigates the history and meaning of statelessness in the period from 1914 to 1945. The course begins with the peace settlements that followed the Great War, which left millions of displaced persons unable to return home, and turned millions more into unwanted minorities in newly formed nations. It asks how statelessness emerged as a `problem’, then looks at the various solutions that were attempted: national ones, such as the unprecedented population exchange between Greece and Turkey; imperial ones, imposed by Britain and France in the mandate territories of the Middle East; and international ones proposed by the newly-established League of Nations. It also looks at how and why governments actively used statelessness as a weapon against parts of their own population from the `White Russians’ who left the USSR after the Russian civil war, to the members of the Ottoman dynasty expelled by the new Republic of Turkey, to the German Jews denationalized by the Nazi regime. The course ends by examining the new crises of statelessness, and new attempts to solve them, that followed the Second World War.