The effectiveness of the many rights and obligations under EU law rests on a legal framework consisting of direct application of Treaty rules, harmonized European rules, national rules, and mutual recognition, and the task of implementing and ensuring compliance with these rules lies, in practice, with a large number of public authorities in the twenty-eight MS. In order to carry out this task, MS’ authorities need to cooperate closely, meaning that administrative cooperation is not only desirable but is required by the very nature of the EU. In the context of the free movement of goods, many circulation regimes are accompanied by their own specific mechanism of administrative cooperation.