This study reports on 2 upper-elementary teachers' learning through their use of potentially educative mathematics curriculum materials without additional professional development. 41 observations of the teachers' mathematics lessons and 28 interviews of the teachers were collected from October to May of an academic year. The case study analyses indicated that curriculum materials can be an effective professional development tool, but perhaps not for all teachers. 1 teacher's instructional focus and rationale for instructional practices remained stable throughout the school year, whereas the other's changed dramatically. The cases illustrated the teachers' dynamic and divergent nature of opportunities to learn through reading materials and enacting lessons. Findings also indicated that consideration of the interaction between beliefs integral to teachers' identity and those that are targets for change may illuminate responses to potentially educative curriculum materials. Teacher learning is widely acknowledged as critical to educational reforms.

Although textbooks and other curriculum materials are ubiquitous in American schools (Woodward & Elliot, 1990), researchers are just beginning to investigate the contributions of curriculum materials designed to support teacher learning (Remillard, 2000; Schneider & Krajcik, 2000). The purpose of this article is to report a study of two elementary teachers' use of and learning from curriculum materials designed to support teacher learning in addition to providing a sequence of mathematics lessons for students.