This paper is an ethnography of a high school mathematics department that has been struggling with curriculum change since 1977. A literature review of curriculum reform revealed four elements of mathematics reform: (1) a focus on students' complex thinking; (2) a change in locus of authority in the classroom; (3) a change in student roles; and (4) an emphasis on ongoing professional development. These four elements were taken as the focus of this high school mathematics department, either directly or indirectly. This paper describes the following aspects of these four elements: the focus on students' learning to think in complex ways that led teachers to search for materials that used this approach; the negotiation that ensued around the locus of authority, as well as the changes in roles of students and teachers; and finally, the informal, national network of teachers and higher education professionals that was important to the professional development of the teachers. These elements comprised the bulk of the reform efforts at this school. (MKR)