This report explains the work that has taken place over the last decade in Boston to not only improve pre-K, but to build on the successes of pre-K through reform of classroom environments, instructional practices, and curricula in pre-K, kindergarten, and, more recently, in first and second grade. It is a story of reforming from the bottom up, of realizing that the work of increasing student achievement is not confined to a single grade, but requires sustained efforts to improve the grades that follow, efforts that persist despite multiple changes in district leadership. It is a story of the importance of using research and data to drive continuous improvement. It is a story worthy of attention from all states and districts across the country working to build on the gains made as a result of high-quality pre-K programs.