This study attempts to define turnaround schools in California, both what constitutes low-performing or "failing" schools and what constitutes turnaround or "success" for these schools. The study clearly specifies the criteria used for identifying and selecting turnaround schools and then provides summaries of the strategies that a sample of principals from these schools reported as essential to their schools' improved outcomes. The authors' set of criteria, developed in conjunction with a group of California education stakeholders, is not proposed as the sole definition for school turnaround; rather, the study intends to provide a definition of both low performance and turnaround for schools in California. The authors applied these criteria to all California schools using data from a seven-year period to identify these schools. They then interviewed the selected schools' principals to identify the strategies they believed were responsible for their turnaround success. The report begins by reviewing different approaches for defining school turnaround and the various turnaround strategies identified in previous studies. It then describes the methods used in this study to define and select turnaround schools in California and present the selected schools' demographic and achievement patterns. Subsequently, it describes the data collection and analysis procedures, followed by eight overall strategies identified across the schools and three individual school profiles. It concludes with implications for policy and practice. [The California Comprehensive Center at WestEd is a partnership with American Institutes for Research (AIR) and School Services of California.]