The Formation of National Party Systems: Federalism and Party Competition in Canada, Great Britain, India, and the United States, Pradeep K. Chhibber and Ken Kollman, Princeton: Princeton University Press, 2004, pp. xvi, 276.

Mining electoral data to arrive at theories about the relationship between political party performance and party system determination and electoral and governmental institutions forms the main stream of political science. And one of its most enduring puzzles is the explanation of the patterns and diversities of party systems. With the famous “Duverger's Law” about single-member plurality systems and two-party political systems forming its point of departure, political scientists have attempted to substantiate their discipline's status as a “science” by producing theories about relationships between measurable political variables.