In a cogent, detailed analysis, the author ‘reconstructs’ the legal order of the European Union in a way that best gives meaning to the Treaties, the case law of the Court of Justice, and the various underlying principles of integration that have emerged over the decades. He focuses on instances, or touchstones, in relation to which EU law seems to be building and integrating an ordre public. Among these are the following: international trade law and arbitration; public international law; the ECHR and EctHR; public policy exceptions to the four freedoms; European citizenship; competition law; national and EU procedural law; and protection of social and labour standards. In-depth inquiry into questions which seem subject to very specific limitations – such as when national or EU courts are under an obligation to raise issues of EU law of their own motion, or norms from which private parties may not deviate – captures the breadth of the EU ordre public, greatly clarifying the concept and the variety of ways it operates. Seeking to reconcile numerous strands and processes of EU law in a principled manner, the book reveals a significant potential for a deeper constitutional framework defining the EU ordre public and putting it into operation as a tool to help ensure unity in diversity. It will be welcomed and read closely by jurists, policymakers, and interested academics in Europe and wherever the matter of European integration is studied.