What is school culture? How can it be measured, described and contrasted? This book investigates school culture and its relationship to school improvement. It describes a three phase,mixed methods approach used to study three pairs of matched schools over a 15 month period. Phase I presents a multi-disciplinary literature review spanning psychology, sociology, business management, anthropology, and educational administration. A new conceptualization of school culture is presented consisting of four dimensions: I: Professional Orientation, II: Organizational Structure, III: Quality of the Learning Environment, and IV: Student-centered Focus. Phase II utilizes the new framework to describe the cultures of six schools. Case studies present thick descriptions of the starkly different organizational cultures at these schools. In Phase III the cultures of matched schools are contrasted. Cross-case comparisons reveal common cultural patterns present in improving schools, and others common to non-improving schools. Striking differences were found in Dimension I. Professional Orientation, and Dimension II. Organizational Structure.