Book excerpt: For all that is revealed in the research literature identifying and describing traits and behaviors exhibited by principals who make a positive difference in student learning, many schools are still failing. With all we know, how does this continue to happen? The goal of this study was to develop theory to expand and enrich the existing research by defining and describing what three successful principals---a middle school and two junior high schools---did to turn their failing schools around and positively influence the levels of student achievement in their respective schools. The significant contribution this study adds to the field of educational research is its identification of five themes or categories of leadership implemented by the principal in each of the schools studied that were credited by the participants as causes for their schools' successful turnarounds. These five categories---expectations and accountability, leadership, responding to student needs, climate and culture, and instruction---and their indicators were consistently identified by the participants in all schools as reasons why their schools were successful in improving student performance levels and each school's achievement status. Clearly, the five categories were interrelated and interdependent upon each other and thus, equally critical to the success the schools experienced.