"The Rewards of Perseverance" tells the story of a district with a clear vision, stable leadership, and deliberate evolution in response to change. Located just north of Houston, AISD has faced daunting challenges since the 1990s--including a significant increase in high-need students, and more rigorous state tests. At the same time, the district has achieved impressive student outcomes, narrowed achievement gaps, and maintained a high graduation rate. Rather than address challenges one school at a time, AISD took a long-term, "whole-system" approach to reform focused on creating the conditions for great teachers and school leaders to succeed. This case study is the second in a series where we track the transformation journeys of leading districts in the context of School System 20/20. After a decade of partnering with urban school districts nationwide, ERS has seen an array of challenges but also beacons of hope. Drawing from this experience, we created School System 20/20, a vision for school system success and a series of assessments that allow districts to measure and monitor how well they use their resources--people, time, and money--to support excellent instruction. Our first case study, "Back from the Brink," examined the rapid, encouraging progress of Lawrence Public Schools, located in the Boston area. [For "Back from the Brink: How a Bold Vision and a Focus on Resources Can Drive System Improvement System," see ED560049.]