This book analyses emerging constitutional principles addressing the regulation of the internet at both the national and the supranational level. These principles have arisen from cases involving the protection of fundamental rights. This is the reason why the book explores the topic thorough the lens of constitutional adjudication, developing an analysis of Courts' argumentation. The volume examines the gradual consolidation of a "constitutional core" of internet law at the supranational level. It addresses the European Court of Human Rights and the Court of Justice of the European Union case law, before going on to explore Constitutional or Supreme Courts' decisions in individual jurisdictions in Europe and the US. The contributions to the volume discuss the possibility of the "constitutionalization" of internet law, calling into question the thesis of the so-called anarchic nature of the internet.