1 Introduction; 2 EU Territory and the Territorial Jurisdiction of the Member States; 2.1 Introduction; 2.2 Who or What Are the Member States Mentioned in Article 52(1) TEU?; 2.3 Member States’ Territory; 2.4 Synthesis of This Chapter; 3. Variable Intensity in Application of the Acquis Throughout EU Territory; 3.1 The Territorial Scope of Primary EU Law; 3.2 Secondary EU Law Follows Suit, but Sometimes Deviates; 3.3 Lack of Cross-Border Element Within the Internal Market: EU Law Does Not Apply Ratione Loci; 3.4 Opt-out and Opt-in; 3.5 Territorial Scope Is Inherent to Field of Policy or Legislation; 3.6 National/Regional Extension Through Voluntary Harmonisation by Legal Transplantation; 3.7 Ad Hoc Commitments; 3.8 Extension to Third Countries Through Treaties and Voluntarily Through the Brussels Effect; 3.9 Synthesis of This Chapter; 4. Geographical Nexus of the Facts of a Case With EU Territory; 4.1 Free Movement Law: EU Citizens in Third Countries and Third-Country Nationals in the EU; 4.2 Competition Law; 4.3 Data Processing by Third-Country Controllers or Processors and the GDPR; 4.4 Ships Flying the Flag of a Third Country; 4.5 Airplanes: Third-Country Air Carriers and EU Air Carriers; 4.6 UN and EU Primary Sanctions and US Secondary Sanctions; 4.7 Third-Country Companies Supplying Goods/Services to Customers in the EU; 4.8 EU Legislature’s Intention of Extraterritorial Reach; 4.9 Extraterritorial Reach, Effects or Jurisdiction of EU Law to Third-Country Situations; 4.10 Synthesis of This Chapter; 5 ConclusionWith increased globalisation, digitisation, cross-border movement of persons and multinational businesses, events and cases have progressively become transnational. Conversely, with the current geopolitical climate, increase of migration and recent pandemics, borders have regained importance. These developments raise questions about the territorial scope of legislation. In this book, 28 mechanisms have been identified which influence the territorial scope of EU law. By using these mechanisms, the territorial scope of any rule of EU law can be determined. The mechanisms relate to decolonisation, overseas countries and territories, disputed borders and territorial claims, Brexit, accession, enhanced cooperation, opt-in and opt-out, the Brussels effect, etc. In addition, this book covers various fields of EU law (free movement rules, migration law, the GDPR, competition law, VAT, sanctions, etc.). The book is unique and stands out from other EU law books, because it encompasses all mechanisms relevant to mapping the territorial scope of the different fields of EU law. It is written for academics, practitioners, policymakers and lawmakers alike.