The Faces of Reason traces the history of philosophy in English Canada from 1850 to 1950, examining the major English-Canadian philosophers in detail adn setting them in the context of the main currents of Canadian thought. The book concludes with a brief survey of the period after 1950.

What is distinctive in Canadian philosophy, say the authors, is the concept of reason and the uses to which it is put. Reason has interacted with experience in a new world and a cold climate to create a distinctive Canadian community. The diversity of political, geographic, social, and religious factors has fostered a particular kind of thinking, particular ways of reasoning and communicating. Rather than one grand, overarching Canadian way of thinking, there are "many faces of reason," "a kind of philosophic federalism".

The book has two dimensions: "it is a continuos story which makes a point about the development of philosophical reason in the Canadian context.... it is a reference work which may be consulted by readers interested in particular figures, ideas, movements, or periods."