The National Center on Scaling up Effective Schools (NCSU) is a five-year project working to develop, implement, and test new processes to scale up effective practices in high schools that districts will be able to apply within the context of their own unique goals and circumstances. This report describes the activities and findings of the first year, specifically, from fieldwork conducted in four case study high schools in one of its partner districts, Broward County, Florida. The findings from this fieldwork inform a joint team of researchers, designers, and district educators toward promising practices around which an innovation will be built in the same district in years three, four and five of the Center's work. The report is divided into ten sections. After an introduction, Section II presents eight essential components of effective high schools drawn from a comprehensive review of the high school reform literature (e.g., Dolejs, et al., 2006; Murphy, Elliott, Goldring, & Porter, 2006) and two others that emerged from the analysis of the fieldwork data in Year One. Section III details the research design, describing the sample selection, data, and three-stage approach used to analyze the data. In Section IV, the authors present case summaries of each of the four sites, referred to herein as B101, B102, B103, and B104 to protect confidentiality. In addition to summarizing the practices through which the essential components were manifest in each school, this section includes structural and demographic features that may be important for contextualizing the findings. In Section V, the authors compare higher and lower value-added schools in terms of the ten essential components and identify the bundles of practices that might explain observed differences. Section VI points to practices that the findings suggest cut across various components to support school success, with particular attention to their major finding on personalization for academic and social learning. The authors also conclude with the next steps for the Center. Appended are: (1) Definitions of Subcomponents and Dimensions; (2) NVivo Code List; (3) CLASS-S Findings; and (4) PASL Case Examples. (Contains 6 tables, 7 figures, and 5 footnotes.)