Teachers often want new ideas and approaches to improve their teaching but their efforts are often blocked by structural constraints in their districts and schools. This book answers the question of how schools can overcome these barriers to provide more supportive environments for change through the study of six cases of schools and districts in which teachers and researchers collaborated to develop teaching for understanding in math and science. This book provides: (1) a conceptual model of how school resources relate to teaching and learning focusing not only on material resources such as time and money, but also on human and social resources; (2) methods that administrators can use to support teachers who want to improve their teaching of math and science; (3) elements that professional developers should look for in a school environment when they are considering working with staff on teaching improvement; and (4) answers to important questions including how schools operate as organizations, how they control work, how they respond to changes in their environment, and how they improve classroom teaching and learning. (KHR)