The knowledge-base of teacher education contains substantial information and recommendations for effective professional development (both in- and pre-service), such as, for mathematics teacher education, a strong content focus grounded in the mathematics teachers will address within the curriculum. However these programs are only half the equation. The participants in any professional development are an unknown. We have little understanding of why and how different participants value different experiences. Because of the current challenges faced by middle school mathematics teachers, this inquiry uses a new research-based in-service master's program in middle school mathematics as a context to explore this unknown.

Challenging culturally embedded views of what it means to know mathematics, this research began with the assumption that, in part, what teachers know and how content is experienced are consequences of teachers' dynamic relationships with the discipline. This relationship represents the interaction, around the content, of identity formation and the personal process of coming to know mathematics. This exploration draws on Wenger's (1998) constructs of identity—in terms of historical experiences/perspectives and participation in the school mathematics community of practice—and Handa's (2006) constructs of coming to know—as the processes of developing propositional knowledge, developing intimate understanding, or their combination—to develop rich, complex stories around two elementary-certified middle school teachers' relationships with mathematics.

The starting assumption behind this research was supported as identities and ways of knowing proved invaluable in understanding the growth that occurred, and the difficulties these teachers encountered, in the doing of mathematics. These relationships also evolved in response to their experiences. As courses were experienced and valued according to these two teachers' relationships rather than by program designers' intended purposes, this suggests that to facilitate growth, programs will benefit from incorporating and promoting explicit opportunities for each teacher to understand, respect, and critically examine her own relationship with mathematics. Supporting teachers as they engage in this challenging work also seems critical.