The Canadian party system is a deviant case among the Anglo-American democracies. It has too many parties, it is susceptible to staggering swings from election to election, and its provincial and federal branches often seem unrelated. Unruly and inscrutable, it is a system that defies logic and classification – until now. In this political science tour de force, Richard Johnston makes sense of the Canadian party system. With a keen eye for history and deft use of recently developed analytic tools, he articulates a series of propositions underpinning the system. Chief among them was domination by the centrist Liberals, stemming from their grip on Quebec, which blocked both the Conservatives and the NDP. He also takes a close look at other peculiarities of the Canadian party system, including the stunning discontinuity between federal and provincial arenas. For its combination of historical breadth and data-intensive rigour, The Canadian Party System is a rare achievement. Its findings shed light on the main puzzles of the Canadian case, while contesting the received wisdom of the comparative study of parties, elections, and electoral systems elsewhere.