This paper uses Renato Rosaldo's metaphor of a "cultural borderland" to analyze the nature of the "bridge" formed in a case study of school-college partnerships. It examines how collaborative teacher preparation programs can bridge the two worlds of theoretical, normatively based canons of practice and inductively derived maxims of reflective practice in the daily action of teaching. Data were collected in a course for prospective teachers in their junior year, as they taught and retaught three sets of microlessons and received help from instructors. The pre-lesson and post-lesson assistance sessions were led by: (1) a full professor who represented the ideal type of applied science, and (2) a teacher on leave from a public school, brought to the university as a clinical teacher, who represented the ideal type of reflective practice. For the reflective practitioners, microteaching was an activity of labor in which moments of "real teaching" were valued for their productivity in the form of students' learning. For the applied scientists, microteaching was an instance of "school learning" in the "real world" of the university in which artificial, simulated teaching enabled the practice of selected teaching skills. The participants' implicit philosophies of teaching practice had implications for collaborative partnerships. (Contains 19 references.) (JDD)