The free movement of persons and services are key elements, alongside the free movement of goods and capital, in the fundamental freedoms which underpin the European internal market. In recent years two key themes have emerged from the case law of the European Court of Justice. The first is convergence in the case law on the free movement of goods, persons, and services in order to ensure the operation of the internal market through the prohibition of discrimination and the outlawing of unjustified obstacles to free movement. The second is the case law on the rights which flow from the introduction of citizenship of the European Union, which offer constitutional rights for individuals. The tensions between these two lines of authority can be explained through a fresh approach to the analysis and synthesis of the Treaty rules and secondary legislation of the European Community, and of the case law of the European Court of Justice on free movement of persons and services. This approach is based on distinguishing between those rules which relate mainly to the regulation of business activities in the internal market, and those which are mainly concerned with individual rights for citizens of the European Union. The result is a detailed overview of the law relating to workers, establishment, and services in the EU in this modern context.