This qualitative account of a magnet school, California's Ibsen School (grades 4-12), addresses teachers' professional identities and the shaping of them. In most high schools, teachers' professional identities are shaped by subject cultures. At Ibsen, a schoolwide community has developed because of its mission and in the leadership of its principal. Characteristics of the principal are described. This case study of Ibsen School illustrates impediments to a schoolwide professional community of secondary school teachers presented by conventional norms of teaching. Described is Ibsen's mission and policy context, its constitutional structure and resources, and indicators of its educational success. The next section highlights the professional roles that distinguish Ibsen teachers' worklives from those of their colleagues elsewhere. The features identified appear most fundamental to the school's success--student-teacher collaboration, personalization, and collective problem-solving. The third section addresses the issue of how each of these distinctive features of Ibsen's community is organized. Finally the cultural themes of Ibsen's community are revisited to highlight the mandates for school leadership presented by such school professional conflicts. (15 references) (RR)