In January 2020, the University of Applied Sciences of Fulda in Germany and the Aristotle University of Thessaloniki in Greece initiated a bilateral university partnership with a collaborative research and teaching project in the field of social security coordination and migration (www.sosec.eu). Stamatia Devetzi and Angelos Stergiou are the initiators and leaders of this university partnership. Within the framework of this project’s work, we had the pleasure to organise on 4 December 2020 an online comparative law conference, upon which this book is based.