Focusing on the case write-up within the Harvard case method of instruction, this study provides historical and empirical evidence for the theory of genre systems. The Harvard case literature and interviews at a case-based business school in the Harvard tradition show that the purpose of this largely ignored written genre is to prepare students to participate in the primary genre, oral classroom discussion of the case. The case genre system provides highly conventionalized conductor-choreographer roles for instructors and blunt, detached consultant roles for student writers/speakers who repeatedly enact decisive, adversarial personae affirming practices and values of the business school.