The present volume is based on an international summer school on migration, asylum and refugee law that took place in Barcelona in the fall of 2018, sponsored by the German Academic Exchange Service and in cooperation between the universities of Barcelona and Hamburg. In the spirit of intergenerational academic exchange, students, young researchers, and established experts engage in interdisciplinary discussions on fundamental questions of migration law and migration policy, which have become more virulent than ever since the refugee protection crisis of 2015. European, human rights and international law aspects are supplemented by national perspectives from Belgium, Bulgaria, the Federal Republic of Germany, Italy, Spain, Turkey and the United Kingdom. The entire project sees itself as a laboratory for the exchange of ideas, for reflection and further thinking about what open constitutional states, the European Union and the international community are equally challenged by today: a migration regime based on human rights, which takes into account security interests and is practicable in a world in which more and more people from ever more different backgrounds are seeking a future beyond their country of origin.