Book excerpt: This book investigates how liberal parties have evolved over time as a party family, in a comparative perspective. Through a discussion of the applicability of the concept of party family to liberal parties, it gives a better picture of the development, challenges, and opportunities for liberal parties in Europe. The history of liberal parties in Europe is peculiar and the origins of the liberal family are not clearly defined. Liberal parties are still quite heterogeneous given the various meanings embraced in the idea of liberalism, including economic liberalism, cultural liberalism, progressivism, social-liberalism. Bringing together the best specialists engaged in the study of liberal parties, and with a two-levels perspective (comparative and case study), this book renews and expands our knowledge on the liberal party family in Europe. Four major themes are developed, linked to the four approaches of the concept of party family: electoral performances, participation to power, ideology and political program, and party organization. These themes are systematically developed in case studies, and in comparative chapters. Primarily aimed at scholars and students in comparative politics, this book should especially appeal to scholars in the fields of political parties and party systems, representation and elections, voting behavior, and public opinion.