Chapter 2 discusses the notion of populism as approached in the political science, legal, and economic literature. It explains in detail how populism is understood in the book, what actions it is associated with, what its principal characteristics are, and what are the possible reasons behind the success of populist politicians. It analyzes the difficult relations between populism and liberal democracy and liberal markets. In particular, by studying the experiences of Hungary and Poland, the chapter provides the reader with two case studies which can be used in an analysis of how a populists’ government’s rule specifically affects liberal democracy and liberal economy. This discussion provides the reader with a concrete context within which the influence of populism on competition law systems can be studied. The chapter concludes with a finding that populism may work as a driver of illiberal change in democracy and the economy.