This book has been conceived in a period where transnational solidarity and co-operation seemed to be moving backwards rather than forwards. A prime example of this decline of transnational solidarity being the so-called refugee crisis in Europe in 2015. After the Brexit referendum in the UK in June 2016, and presidential elections in the USA later the same year, the political agenda turned inwards, focusing primarily on internal national perspectives in relation to areas such as environmental protection, aid to countries in the Third World and trade with the outside world. Recently, the EU has experienced a number of crises, among others an economic and financial crisis and later the refugee crisis. These crises have challenged transnational solidarity in Europe.