The turnaround recommendations and framework in "The Turnaround Challenge" grew out of both new research and synthesis of extensive existing research, as carried out by Mass Insight Education & Research Institute and its partners since September 2005. If the main report is the tip of the proverbial iceberg, this supplement represents at least part of the mass underneath it. In the course of preparing the main report, the authors examined state and district intervention strategies and high-performing, high-poverty schools at a deeper level of specificity than what the design of the main report allowed them to present. The highlights of that research are presented here in this supplement, along with a more extensive probe into poverty's impact on learning and the consequent implications for the design of high-performing schools serving high-poverty enrollments. Readers of "The Turnaround Challenge" should therefore regard this supplement not as a separate report, but as a set of "drill-downs" at four levels: (1) State: Brief profiles of ten representative state strategies to intervene in failing schools; (2) District: More detailed exploration of four high-profile district experiments in school turnaround; (3) School: Close analysis of five high-performing, high-poverty schools that can help us visualize the end goal of turnaround efforts; and (4) Student: Summary of emerging research on the three categories of impact that poverty has on students' readiness to learn. (Contains 36 resources.) [For the main report, "The Turnaround Challenge: Why America's Best Opportunity to Dramatically Improve Student Achievement Lies in Our Worst-Performing Schools," see ED538298. For "The Turnaround Challenge: Why America's Best Opportunity to Dramatically Improve Student Achievement Lies in Our Worst-Performing Schools. Executive Summary," see ED538309.]