Though metropolitan Boston is still one of the nation's whitest metropolitan areas, its growth is increasingly non-white and multiracial. Given the demographic trends and the high fragmentation that characterizes the metropolitan area, students are most segregated in regions where they are highly concentrated: black students in Boston, Latino and Asian students in certain satellite cities, and white students in the suburbs. The segregation is not just by race or ethnicity but is increasingly by language. High levels of segregation are also very dramatically linked to social and economic differences, proportion of credentialed teachers, and to differences in schooling outcomes such as MCAS scores and completion rates. Segregated minority schools are markedly less successful in terms of academic achievement as measured by the state's mandated tests. The following are appended: (1) Area Definitions; (2) Minority Share of Enrollment and Districts with Less than Half of 10th Graders Scoring at Proficiency Level or Better on English MCAS; and (3) Minority Share of Enrollment and Districts with Cumulative Promotion Index Less than 50 Percent. (Contains 20 tables, 9 figures, and 75 notes.)