The book explores how the European Union and its members have been renegotiating Europeanisation and renationalisation in response to the multiple crises they faced in recent years. The authors highlight varying understandings of crises in different national and supranational policy and institutional contexts. They show how in some cases these have challenged the legitimacy of European Union norms and institutions and even triggered disintegration, while in other cases these crises have served as sources of inspiration for European social innovation and political development.