What makes the relationship between Switzerland and the EU so challenging? For both parties, mutual relations are of crucial importance, not least economically. As a result of the Swiss voters' rejection of the European Economic Area 30 years ago, there is at present a large number of agreements agreements that provide for Switzerland's partial participation in the EU's internal market as well as other matters. At the same time, there has now for more than a decade been an increasing degree of institutional and legal uncertainty. The present volume offers an inventory of different sides of this special relationship, which is interesting also in a comparative context.