Party system closure: party alliances, government alternatives, and democracy in Europe Oxford: Oxford University Press, 2021. $100.00, 320 Pages

Party System Closure. Party alliances, Government Alternatives, and Democracy in Europe (Oxford 2021) written by Fernando Casal-Bertoa and Zslot Enyedi is a unique, informative and insightful longitudinal study of how European countries were governed in the last century. Before assessing the methodological advancements that the book proposes in the study of party system institutionalization, it is worth noting that scholars and students who are not famil-iar with this branch of political science will find in the book a massive amount of information about governments in small and big countries in Europe. The book includes data for much-analysed countries in Western, Eastern and Southern Europe, but also for micro-states (such as San Marino, Andorra and Liechtenstein) or other under-analysed countries (Albania, Moldova, Montenegro, North Macedonia). The third chapter in this regard provides a very informative analysis of the functioning of current party systems in Europe, while chapter four adds to this an historical account of defunct party systems (24 in total). The geographical scope allows the authors to both drawing inferences from the whole universe of elections in Europe (and not just a sample of them). This is per se an ambitious achievement; yet, Casal-Bertoa and Enyedi go beyond this, adding to a cross-time dataset a new analytical perspective which constitutes a significant step forward in the study of European party systems. In fact, the explicit aim of the book is to present a new measurement, based on the patterns of parties ’ interactions in government, for the often-elusive concept of party system institutionalization. The authors, drawing from the work of Peter use the concept of ‘ closure ’ to measure