This paper describes the difficulties that two prospective teachers experienced in student teaching assignments in two city schools; both judged outstanding by the faculty from where they were about to graduate. It examines the ways in which these experiences eroded the student teachers' convictions that they could teach all children in ways that emphasized student construction of meaning. Examination of their journals and reflective writing showed how the many demands of classroom teaching and the pressures generated by a traditional staff-room culture together created an environment in which two young women who had believed themselves to be fully committed to progressive practices came to see these reform ideas as visionary and impractical. Findings of the analysis suggest that even the most committed novices are vulnerable to staff-room culture and that a professional community outside of the school that raises questions about the practices the novices are trying to implement can help them to connect the ideas they valued as students with the reality of the real-world classroom. (NAV)