This study examined the processes of change in thinking as a means of learning about the professional development of two science teacher educators. A qualitative methodology was used. The main research tool was a semistructured in-depth interview. The primary data analyzed came from two science teacher educators, selected from a broader set of seven. Findings emphasize the importance of questions regarding the knowledge possessed by teacher educators and of the questions regarding the role of science teacher educators. That is, the knowledge of an expert science teacher educator was more than a list of givens; it was personal and context-bound. This study contributes new insight into the processes of teacher educators' professional development and change in their thinking. (Contains 1 note, 2 tables, and 1 figure.)