This is an exploratory, descriptive study of experienced elementary, middle, and secondary school teachers who participated in a 9-month cooperative learning training project which was designed to encourage reflection upon their beliefs and assumptions about their pedagogy. Fifteen teachers were interviewed to understand how teachers modify cooperative learning to fit their existing beliefs about pedagogy; how teachers interact with this innovation to reconstruct their assumptions about teaching and learning; and how these reconstructions affect certain pedagogical themes which emerged from them. Themes which emerged were: conceptions of their role, their sense of authority and locus of control, their notions of the nature of knowing and knowledge, their conceptions of their decision-making, their understanding of cooperative learning, and their resolution of the dilemmas of practice which emerge for them in the process. Using a model which defined three broad epistemological orientations, or meaning systems, operating on a continuum from "transmission" to "transaction" to "transformation," which cast educational practices as systems of belief, the mainstream models of cooperative learning were analyzed for their fundamental assumptions regarding these themes. (Author/IAH)