As the anniversary of "Brown v. Board of Education" decision arrives again without any major initiatives to mitigate spreading and deepening segregation in the nation's schools, the Civil Rights Project adds to a growing national discussion with a research brief drawn from a much broader study of school segregation to be published in September 2016. Since 1970, the public school enrollment has increased in size and transformed in racial composition. Intensely segregated nonwhite schools with zero to 10% white enrollment have more than tripled in this most recent 25-year period for which we have data, a period deeply influenced by major Supreme Court decisions (spanning from 1991 to 2007) that limited desegregation policy. At the same time, the extreme isolation of white students in schools with 0 to 10% nonwhite students has declined by half as the share of white students has dropped sharply. This brief shows states where racial segregation has become most extreme for Latinos and blacks and discusses some of the reasons for wide variations among states. It calls attention to the striking rise in double segregation by race and poverty for African American and Latino students who are concentrated in schools that rarely attain the successful outcomes typical of middle class schools with largely white and Asian student populations. Further, it shows the importance of confronting these issues given the strong relationship between racial and economic segregation and inferior educational opportunities clearly demonstrated in research over many decades.