evidence. After pages of documentation on the ineffectiveness of structural innovations in education, Stephens hypothesized that effective teaching depends upon the "lively interests of teachers."2 This paper is a review of the attempts to assess the relationship of enthusiasm to pupil achievement and to specify the behavioral components of enthusiasm. Correlational and experimental studies in classrooms ranging from elementary school to college will be examined. I shall discuss the results of the studies, estimate the relevance of the results to teacher training programs, and suggest directions for future research. An important element of this paper is the discussion of how high-inference and low-inference measures can be used together in the study of teaching.