This report provides a detailed descriptive analysis of the principals who led Illinois public schools from 2001 through 2008. The authors begin with a brief historical review of the research literature on educational administration to provide a foundation for understanding the broader context for this study. Using state administrative records and other associated data, they assembled a large database of approximately 3,900 schools and their principals for each academic year. By linking numerous school and individual characteristics and tracking the placement and movement of building administrators, they used these data to analyze whether any patterns in the distribution of principals could be observed. Appendices include: (1) The Availability of ACT data; and (2) The Regional Nature of School Demographics, Locale, and College Competitiveness in Illinois. (Contains 37 figures, 7 tables, and 4 footnotes.)