A report is given of findings from a study of beginning teachers' development of "knowledge-in-action," Schon's (1983) term for knowledge that is apparent in a professional's day-to-day actions. Participants were observed and interviewed frequently during their practice teaching placements. Transcripts of lessons and interviews were prepared for analysis, providing a data base for comparisons over time and across participants. One subject was followed through a 14-week internship as a student teacher and through the first six months of her first year of teaching. Another was followed through six weeks of practice teaching and the first two months of his first year of teaching. Focus was upon what novice teachers were learning to do in the classroom, rather than what they had been taught in the classroom of their teacher education program. The report begins with extracts from selected literature on the process of learning to teach and goes on to discuss the perspectives of several of the participants, using excerpts from transcribed interviews to illustrate how they view the process of developing personal professional knowledge of teaching. (JD)