Changing classroom demographics and increasing demands for a more highly educated population have given rise to increased calls for education reform across the United States. In order to make meaningful, dynamic differences in the quality of education for students, educators and school districts must find professional development opportunities for teachers that are sustainable over a long period, are teacher-led in collaboration with peers, are based on meaningful inquiry, and are inexpensive. One such response to these demands is the creation of Professional Development and Inquiry Groups (Clark, 2001). In these groups, teachers meet to converse and to study teaching and learning. Such groups, also called teacher study groups (TSGs), are forming across the United States as teachers approach professional development as a way to learn about teaching and learning through conversation.