In the immediate aftermath of the First World War, Upper Silesia was the site of the largest formal exercise in self-determination in European history, the 1921 Plebiscite. This asked the inhabitants of Europe s second largest industrial region the deceptively straightforward question of whether they preferred to be Germans or Poles, but spectacularly failed to clarify their national identity, demonstrating instead the strength of transnational, regionalist and sub-national allegiances, and of allegiances other than nationality, such as religion. As such Upper Silesia, which was...