The authors explore three core competencies of high-performing school systems: (1) understanding what the work is--a deep understanding of the core business of facilitating learning, a vision of what that looks like, and an awareness of where the system is in relation to that vision; (2) knowing how to do the work--a theory of action for improving instruction, a focus on key strategies, and effective alignment of resources; and (3) building the individual and organizational "habits of mind" that foster continuous improvement. Each chapter includes examples that illustrate key concepts in action, questions to spur self-assessment in key areas of competence, and tools and resources for building capacity at different levels and stages of development.