Book excerpt: Realising the goal to develop a common immigration policy introduced with the Treaty of Maastricht and further developed since then (see currently Article 79 TFEU), the EU has, in the recent years, adopted legislation on the access of third-country nationals (TCNs) to the EU and their legal situation in the Member States. The various EU migration Directives grant rights to residence and labour market access, require equal treatment with nationals of the host Member State, provide for family reunification, address the issue of social security coordination and guarantee mobility within the EU. As a consequence, the legal situation of TCNs has, to a certain degree, approximated to that of EU workers enjoying free movement since the beginning of European integration. Nonetheless, important differences remain: First, while the free movement of EU workers is guaranteed by directly enforceable provisions of EU primary law, similar rights for TCNs depend on the enactment of EU secondary law. This implies a wide margin of discretion in designing the regime - notwithstanding fundamental rights requirements such as the right to family life (Article 7 Charter of Fundamental Rights). Second, while all EU workers fall within the personal scope of application of the EU free movement rules (uniform and comprehensive notion of EU worker), the intra-EU mobility regime for TCNs is based on a sector-specific approach with Single Permit Directive 2011/98/EU having a certain residual function. The latter introduces a single application, procedure and general provisions on equal treatment and does not distinguish between a first application for a permit and following intra-EU mobility. Rules with a general scope of application only exist for family reunification and long-term residents (both requiring previous admission to the EU, though). Third, while EU workers enjoy unrestricted labour market access in the EU Member States, significant restrictions such as quotas or preference rules apply to TCNs. Fourth, while EU workers enjoy a comprehensive claim to equal treatment with nationals of the host Member State, such a general prohibition of discrimination does not exist with regard to TCNs. Rather, the EU migration Directives stipulate specific claims to equal treatment subject, moreover, to limitations. Fifth, the right to residence of TCNs is subject to limitations not applying to EU workers. Sixth, the social security coordination regime applies to TCNs legally residing in a Member State. However, there are still no EU instruments on social security coordination with third countries. Seventh, also family reunification with regard to TCNs is subject to stricter conditions than in the context of EU workers. Finally, while the rules on free movement of EU workers do not distinguish between a first establishment in one Member State and subsequent establishment(s) in other Member States and do not apply different rules to these situations, the EU migration Directives are based on such a distinction.