This report presents the final results of a four-year independent external evaluation of the impacts and implementation of the scale-up of Reading Recovery, a literacy intervention targeting struggling 1st-grade students. The evaluation of Reading Recovery includes parallel rigorous experimental and quasi-experimental designs for estimating program impacts, coupled with a large-scale, mixed-methods study of program implementation under the Investing in Innovation (i3) scale-up. The primary goals of the evaluation are to: (1) Provide experimental evidence of the short- and long-term impacts of Reading Recovery on student learning in schools that are part of the i3 scale-up; and (2) Assess the implementation of Reading Recovery under the i3 grant, including fidelity to the program model and progress toward the scale-up goals. The impact evaluation includes a multi-site randomized controlled trial (RCT) for estimating immediate impacts, a regression discontinuity study (RD) for estimating longterm impacts, and an implementation study for assessing fidelity of implementation and exploring program implementation in depth. The RCT includes nearly 7,000 randomized students in more than 1,200 schools over four years. The RD study measures Reading Recovery's impacts at the end of first grade and in third grade, and replicates the RCT's immediate post-treatment findings in a separate sample of students. The implementation study involves a combination of qualitative and quantitative research executed on a large scale over the same four-year timeframe. The evaluation's key findings pertain to the following topics: (1) Scale-Up Processes, Challenges, and Outcomes; (2) Immediate Impacts of Reading Recovery; (3) Sustained Impacts of Reading Recovery; and (4) Implementation Fidelity. The authors' analysis revealed strong fidelity to the program model in all of these areas and all years of the scale-up. This suggests that the intervention was delivered as designed to the students in the scale-up, and that teachers delivering Reading Recovery lessons were properly trained. In total, the results of the fidelity analysis support the validity of their impact findings. Three appendices are included. [To view the brief for this report, "Evidence for Early Literacy Intervention: The Impacts of Reading Recovery," see ED586802.]