The Canadian party system is a deviant case among the Anglo-American democracies. 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 that underpin the system. 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.