The Introduction sets the scene by describing the relevance of the idea of a symbiotic relationship between competition and democracy in the history of competition law and the contemporary policy debate. It identifies the gap in the literature, explains the research question and the purpose of the book, and presents the argument of the book in a nutshell. It starts with the observation that the idea of a link between competition and democracy is a recurrent theme in US and EU competition law. However, existing scholarship has so far struggled to clearly explain what the relationship between competition and democracy actually consists of. This knowledge gap is filled by this book which provides a clear, conceptually sound, and surprising answer to this research question. It argues that the idea of competition–democracy nexus is grounded in a republican understanding of liberty as non-domination which can be traced back to the political thought of the Ancient Roman republic and fundamentally differs from our contemporary negative concept of liberty as non-interference. The purpose of the book is to demonstrate how this republican concept of liberty explains the idea of a competition–democracy nexus in US and EU competition law.