This book commenced by noting that the current ‘melancholy’ surrounding the future of the EU should not coincide with the abandonment of the foundational idea of a ‘Social Europe’. The official proclamation of the European Pillar of Social Rights (EPSR), in November 2017, has brought new life to the longstanding debate on the relationship between the internal market and social rights, a theme on which much ink has been spilt so far. However, far less attention has been given to the constitutional framework that identifies, through the ‘social market economy’ clause, the merging of the social and economic dimensions within EU law.