In a world in which change is constant, the principle of self-determination is important. Through (collective) acts of self-determination, nations exercise the right to govern themselves. At present the nation-state system with which we are familiar faces several challenges. In Western Europe, sub-state nationalism is on the rise. In the Middle East and North Africa, the state system bequeathed by former colonial powers faces increasing threats from pan-Islamist movements. Overall, the established order faces unprecedented uncertainties. The scholars who have contributed to this volume...