This book offers insights into the legal mechanisms that are adopted in multilevel constitutional orders to accommodate the tension between contrasting interests of diversity and unity and the converging or diverging effects they may have on the functioning of a multilevel constitutional order. It does so by targeting mainly the European experience but also drawing insights from other jurisdictions. The volume draws on a well-rounded theoretical framework that allows a comprehensive discussion of the dialectics in multi-level systems.) It focuses on two of the most relevant areas of constitutional law, namely the setup of supranational institutions and the protection of fundamental human rights. Finally, the work presents a fresh legal take on the unity-diversity dichotomy. This collection is ideal for academics working in the fields of constitutional law, international law, federal theory, institutional design, management and accommodation of diversity, and protection of fundamental rights. Political scientists will also find the discussions very relevant as a foundation for further research in their field. Policymakers involved in constitutional engineering will be interested, as mechanisms of accommodation, convergence, and divergence are increasingly looked at as devices for managing multilevel polities.