Not only have school choice policies significantly expanded in the last decade, but also the research has become more sophisticated and nuanced. We have moved beyond simple comparisons of student achievement between schools of choice and traditional public schools. With some cities and states that have multiple-choice options, and with increasingly available longitudinal data systems, we can now consider different forms of choice simultaneously while continuing to compare them with traditional public schools. We have also started to move beyond focusing wholly on student test scores that preoccupied the No Child Left Behind era of school reform to consider other important outcomes, such as educational persistence and attainment, socioemotional and behavioral competencies, and long-term workforce outcomes. This second edition of the Handbook reflects these research developments and continuing policy interests. It has been well documented that educational inequalities are persistent and, in some cases, increasing to a wearisome degree. Some have argued that a better way to refer to such gaps—whether between socioeconomic or racial/ethnic or other historically marginalized groups—is as an education debt, a debt that has accumulated over time and cuts across historic, economic, sociopolitical, legal, and moral dimensions (Ladson-Billings, 2006). Students in low-income families are more likely to live in segregated neighborhoods; schools have become increasingly segregated over the past couple of decades; and families in marginalized communities may not have access to