Drawing on sociological and cognitive psychological perspectives on teacher learning, this comparative case study investigates the myriad influences that shape teachers' learning in two divergent teacher education pathways. Specifically, this article explores a case of the two most common pathways into middle school teaching--the elementary and secondary pathways--and their contribution to the preparation of middle school social studies teachers. The findings of this study provide important insights into the instructional practices in which teacher education programs engage prospective teachers, the explicit and implicit purposes toward which these practices are directed, and the program opportunities that support those purposes. The author discusses how these findings inform the preparation of middle school teachers specifically and teacher education practice and policy generally. (Contains 10 tables and 2 notes.)