Populist forces are increasingly relevant, and studies on populism have entered the mainstream of the political science discipline. However, no book has synthesized the ongoing debate on how to study the phenomenon. The main goal of this Handbook is to provide the state of the art of the scholarship on populism. The Handbook lays out not only the cumulated knowledge on populism, but also the ongoing discussions and research gaps on this topic. The Handbook is divided into four sections. The first presents the main conceptual approaches and points out how the phenomenon in question can be empirically analyzed. The second focuses on populist forces across the world with chapters on Africa, Australia and New Zealand, Central, Eastern, and Western Europe, East Asia, India, Latin America, the post-Soviet States, and the United States. The third reflects on the interaction between populism and various issues both from scholarly and political viewpoints. Analysis includes the relationship between populism and fascism, foreign policy, gender, nationalism, political parties, religion, social movements, and technocracy. The fourth part encompasses recent normative debates on populism, including chapters on populism and cosmopolitanism, constitutionalism, hegemony, the history of popular sovereignty, the idea of the people, and revolution. With each chapter written by an expert in their field, this Handbook will position the study of populism within political science and will be indispensable not only to those who turn to populism for the first time, but also to those who want to take their understanding of populism in new directions.