1. Introduction Part 1: Conceptualising differentiation Introduction 2. Studying differentiated integration: Methods and Data 3. On the legitimacy of differentiated integration 4. Differentiated (dis)integration beyond Europe: A Comparative Regionalism Approach 5. De facto Differentiation in the European Union: Circumventing Rules, Law, and Rule of Law 6. Constitutive differentiation 7. EU External Differentiated Integration and Compliance: Theoretical and Legal Aspects 8. From Integration to Fragmegration: Political symbols and the emergence of differentiated European identities 9. Differentiation and segmentation Part 2: Institutionally-based differentiation Introduction 10. An ever more fragmented Union? On the emerging relevance of differentiated integration for governance structures within the EU 11. Promise Unfulfilled? Managing Differentiated Integration in EU Secondary Law Through Enhanced Cooperation 12. Differentiation in the European Parliament: United about diversity? 13. Differentiation and the European Central Bank: A bulwark against (differentiated) disintegration? 14. Differentiation and the European Commission 15. Differentiation and the European Court of Justice 16. Third country participation in EU agencies: Towards "condominio"? 17. The Council of the European Union: Organizational and Social Dynamics of Differentiation Part 3: Policy-based differentiation Introduction 18. Differentiated integration in EU energy market policy 19. Brexit and the Common Fisheries Policy: Opportunities for multi-level differentiated (dis)integration? 20. The European Asylum Policy: Core state powers, flexibility and differentiated integration 21. Differentiated integration in EU climate policy 22. Differentiated integration in European External Action 23. PESCO: A formula for positive integration in European defence 24. The Increasingly Differentiated European Single Market? 25. Differentiation and social policy: A sustainable way forward? 26. Differentiation in EU Security and Defense Policy Part 4: Territorial differentiation Introduction 27. The Nordic countries as pioneers of differentiation 28. Risky Advantageous Differentiation: Iceland and the EEA 29. The Swiss and Liechtenstein relations with the EU – an ongoing institutional challenge 30. Turkey’s external differentiated integration with the EU in the field of migration governance: the case of border management 31. Visegrad Four and EU Differentiated Integration: Activities, Perception and Self-Perception after the Refugee Crisis 32. Poland as the (new) awkward partner: Differentiated integration or differentiated disintegration? 33. Trajectories of Differentiated EU Integration for the Western Balkans 34. European Neighbourhood Policy: Differentiated integration beyond the EU’s Eastern and Southern Borders 35. Differentiation at the local level: An overview of sub-national authority networks in the EU Part 5: Brexit Introduction 36. Brexit as a phenomenon: national solidarity as a tool against the European project? 37. (Post-)Brexit: Negotiating Differentiated Disintegration 38. International perceptions of Brexit 39. Differentiation and Power Asymmetry: How Brexit is Changing UK Relations with Czechia and Slovakia 40. Brexit and Northern Ireland 41. Border Conflicts and Territorial Differentiation after Brexit: The cases of Northern Ireland, Gibraltar and the UK Sovereign Base Areas in Cyprus 42. Growing Apart Together? Brexit and the Dynamics of Differentiated Disintegration in Security and Defense 43. Conclusion. Epilogue: Polycrisis and Resilience in the European Union: Covid-19 and avenues for future studies

"Finally! Everything you ever wanted to know about differentiated integration, and then more. Wish I had this comprehensive handbook when I was writing my PhD on the subject in the 1990s. A wealth of well-structured, clear and accessible information on a complex subject."Alexander Stubb, Professor and Director, EUI, Florence; Former Prime Minister of Finland"Differentiation is here to stay, and at the latest Brexit has made it clear that differentiation in Europe encompasses both integration and disintegration processes. This is the core message of this timely handbook, which shows the breadth of this phenomenon in detail thanks to an impressive list of contributors. It is an excellent go-to resource for all scholars of European Studies seeking to understand the challenges of ‘unity in diversity’."Sieglinde Gstöhl, Director of Studies, College of Europe, Belgium"This handbook is an invaluable resource on differentiation—involving both integration and disintegration—in the Europe Union. Its stellar list of contributors offer a plethora of insights into the many different ways in which the EU has not only differentially integrated with regard to institutions, policy areas and territory, but also dis-integrated, as in the case of Brexit. A must-read for all those concerned with the ins-and-outs of EU integration."Vivien Schmidt, Jean Monnet Professor, Boston University, United States