This book offers a deeper understanding of the dynamics and challenges faced by the ongoing development of European constitutional law. The content and form of European constitutional law are shaped by rules, principles and values found partly in European law and partly in (common) national constitutional norms and international documents, especially the European Convention on Human Rights. Taking the multifaceted and multidirectional nature of European constitutional law as their starting point, the essays in this book are organised around three central themes. The first draws attention to the relevance of concepts such as constitutional culture and epistemic communities and their impact on the design and execution of comparative research in this field; this is particularly useful for understanding the migration of constitutional ideas among legal orders. The second addresses the conceptualisation of European constitutional law by looking at the meaning of constitutional identity, institutional balance, democracy and the notion of the 'composite constitutional order'. The third theme is European constitutional law in action, and considers how national actors operate in this complex environment and contribute to the development of this body of law.