How do teachers adapt to the demands of curriculum change and new educational standards? How do they learn what is expected of them? In this path-breaking work, Jacob Adams examines how a promising new professional structure, the teacher network, helped teachers implement a novel and challenging high school mathematics curriculum and how it fostered teachers' determination and ability to get the job done, when traditional staff development supports did not. Beginning with an in-depth examination of the demands of policy on practice, the author concludes with a practice-based model for professional development and curriculum implementation.