The Coalition of Essential Schools is a school reform movement based on nine principles formulated by Theodore R. Sizer on the basis of several years of research in secondary schools with the goal of creating thoughtful students who will become thoughtful adults. Coalition schools, which numbered 120 in 1992, represent a cross section of American schools and a variety of educational reform practices. This study focuses on eight diverse school sites: six public high schools, one private school, and a newly created secondary school in a district of choice. Three are urban schools with enrollments of about 1,000 students. An ethnographic perspective helps reveal how changes in one facet of schooling affected other areas of school life. Results of 5 years of ethnographic research makes it clear that contemporary school reform efforts in the United States are both institutional and individual phenomena, with implications for school structure and for individuals within the structure. The first section of this book looks at five specific schools undergoing change. The second offers more narrowly focused studies that describe the efforts of individual teachers and administrators from Coalition of Effective Schools members to promote reform. An appendix discusses study methodology. (Contains 176 references.) (SLD)