This paper describes an exploratory study of conceptual change in 91 students enrolled in an introductory course at Michigan State University designed to help beginning teacher education students examine critically their preconceptions. The data consist of essay responses written at the beginning and end of the term. The authors were interested in whether and how students' ideas changed over the course of the term, what factors influenced the changes, and whether the responses of students in a classroom participation observation version would differ from those in the nonfield version of the course. The study analyzed data along four dimensions that represent major themes in the course: (1) traditions of teaching; (2) the relationship of teaching and learning; (3) the contexts of teaching; and (4) the knowledge required of teaching. Besides illustrating changes in students' thinking, the paper also describes goals for student learning and activities that students undertake in the course. (Author/JD)