Ten years after the Charter of Fundamental Rights of the European Union became part of binding primary law, and twenty years since its adoption, this volume assess the application of the EU Charter in the Member States. How often, and in particular by which actors, is the EU Charter invoked at the national level? In what type of situations is it used? Has the approach of national courts in general, and of constitutional courts in particular, to EU law to EU fundamental rights law changed following the entry into force of the Charter? What sort of interplay does the Charter generate with the national bill of rights and the European Convention? Is the life with the Charter on the national level a harmonious 'praktische Konkordanz' or rather a messy 'menage a trois'? These and other questions are discussed in the four parts that form the book. Part I is dedicated to the normative foundations. Part II sets out Member States' Perspectives, providing a structured, in-depth account of the Charter's operation in 16 different Member States. Part III provides a detailed evaluation of selected rights contained within the Charter. Part IV synthesises the materials presented up to that point to develop a series of broader perspectives, looking to discover underlying lessons about the relationship between EU fundamental rights law and national legal systems.