This book is located at the intersection of constitutional law and political science and uses legal network analysis to shed light on hitherto unseen aspects of the citation practices among constitutional courts in Europe. The collection enhances our understanding as to why certain European constitutional courts refer more and others less to the Court of Justice of the European Union (CJEU) and the European Court of Human Rights (ECtHR) on the vertical level and other European constitutional courts on the horizontal level. Divided into two parts, the volume offers novel data on references between European constitutional courts. It provides a coherent and original methodological approach to analyze the case law and draws on research from political science and network analysis to inform the discussion of judicial “dialogue” between them, highlighting an asymmetric dimension. Featuring country-specific analysis by leading scholars, this work is an invaluable reference for academics, researchers, and policy-makers working in EU Law, Human Rights Law, Constitutional Law, and Politics.