Using theory syllabi and departmental data collected for three academic years, this paper investigates the institutional practice of theory in sociology departments across Canada. In particular, it examines the position of theory within the sociological curriculum, and how this varies among universities. Taken together, our analyses indicate that theory remains deeply institutionalized at the core of sociological education and Canadian sociologists' self-understanding; that theorists as a whole show some coherence in how they define themselves, but differ in various ways, especially along lines of region, intellectual background, and gender; that despite these differences, the classical versus contemporary heuristic largely cuts across these divides, as does the strongly ingrained position of a small group of European authors as classics of the discipline as a whole. Nevertheless, who is a classic remains an unsettled question, alternatives to the "classical versus contemporary" heuristic do exist, and theorists' syllabi reveal diverse "others" as potential candidates. Our findings show that the field of sociology is neither marked by universal agreement nor by absolute division when it comes to its theoretical underpinnings. To the extent that they reveal a unified field, the findings suggest that unity lies more in a distinctive form than in a distinctive content, which defines the space and structure of the field of sociology.