Diversified schools, in which students of various racial, ethnic, and socioeconomic characteristics are balanced, have a positive contextual effect on achievement for all groups as compared with schools with homogeneous student bodies that tend to help affluent, white students and harm poor students and students of color. Most studies of school reform offer single-variable solutions such as choice, autonomy, or standards. This nationwide study shows how a better and more permanent reform outcome is achieved when choice, diversity, and school improvement are introduced simultaneously. The authors advise school districts convicted for operating segregated schools on how to make all schools "schools of choice" that must compete for students who enroll in them. They suggest ways of empowering parents and professional educators and discuss how all school districts--urban, rural, large, and small--can achieve both excellence and equity in all schools. School systems reluctant to use racial fairness guidelines in the enrollment process are advised to use socioeconomic fairness guidelines, because the absence of any enrollment fairness guidelines tends to result in the return to segregation and a dual school system helpful to a few, but harmful to many students.