This study was conducted to examine how the organization of preservice teachers' (N=23) knowledge about teaching changed during the last year of their undergraduate program which included a teaching methods course and student teaching. In order to explore cognitive organization three tools were combined: multidimensional scaling, concept mapping, and interviews. Subjects received instruction on how to draw concept maps and were asked to draw them four times--before the senior year, at the end of the fall semester, in the middle of student teaching, and at the end of student teaching. Following each phase, the previous map was returned and subjects were to decide if they would organize their knowledge differently. Prior to an interview they were asked to draw a new map, modify their old one, or redraw the old map as it was. Drawings were coded and scored and the sample concepts of "flexibility" and "planning" were selected for further analysis through multidimensional scaling and student interviews. Data analysis revealed that during student teaching the preservice teachers' pedagogical knowledge underwent radical reconstruction, involving a reorganization of prior knowledge, theories, and beliefs. Figures depicting concept maps and students' multidimensional scaling are included. (Contains 22 references.) (LL)