This book is about rights and powers in the digital age. It is an attempt to reframe the role of constitutional democracies in the algorithmic society. By focusing on the European constitutional framework as a lodestar, this book examines the rise and consolidation of digital constitutionalism as a reaction to digital capitalism. The primary goal is to describe the characteristics of European digital constitutionalism and provide a normative perspective defining the European approach to protect fundamental rights and democratic values in the algorithmic society. This new phase is examined in a two twofold way. Firstly, this book investigates the reasons leading to the rise and consolidation of digital constitutionalism in Europe. Secondly, it provides a normative framework analysing how and to what extent European constitutionalism provides the constitutional architecture to limit the exercise of discretionary powers in the algorithmic society.