This paper concentrates on incidents of severe conflict in eighth-grade classrooms observed in studies of four socially diverse junior high schools in two districts. Severe conflict is generated when teachers violate students' conceptions of the character of legitimate classroom authority. In a cosmopolitan community within an urban complex, students of both high and low social status and academic achievement were unusually skeptical of the schools' good faith. The school staffs had especially small resources for exercizing forms of control other than authority. Consequently, the character and importance of authority emerged with unusual clarity in classroom encounters. In a small, conservative, midwestern city, there was a significant contrast. Neither teachers nor students were self-conscious about the character of authority, and at first glance classroom conflicts appeared to stem from personality characteristics and conflicts. But, analysis of interaction in the light of findings in the first district suggests that, though the participants were less articulate in their claims, adherence to norms defining the legitimate character of authority was as crucial to harmony and conflict in the second district as in the first. (Author)