In June 2007, the Supreme Court limited the tools that school districts could use to voluntarily integrate schools. In the aftermath of the decision, educators around the country have sought models of successful plans that would also be legal. One such model may be Berkeley Unified School District's (BUSD) plan. Earlier this year, the California Supreme Court declined to review the appellate court's decision upholding the legality of the district's integration plan; the decision noted the district did not use students' race-ethnicity in a way that violated Proposition 209, an initiative that prohibits the preferential or discriminatory use of race-ethnicity in public institutions. This report explores the BUSD plan and examines what it offers as lessons in a time of growing demographic and legal complexity. BUSD's integration plan uses two levels of geography--zoning and planning areas, which are 4-8 block groups that are coded according to their racial-ethnic, economic and educational demographics--in its "controlled choice" plan. While managing families' school preferences and a set of priorities, the plan seeks to maximize school diversity so that each school reflects its zone-wide diversity as measured by the planning areas. What is innovative about BUSD's plan is that every student living in a particular planning area is assigned the same diversity code, based on the area's population characteristics regardless of their own individual characteristics. Drawn from a year-long study of the BUSD integration plan, this report reviews the district's historical commitment to desegregation, describes how the current plan works, analyzes the extent the plan desegregates the schools despite being located in racially and socioeconomically segregated neighborhoods, and discusses the plan's implementation including the policies and practices that promote participation in its controlled choice assignment plan and matriculation once assigned. Academic Achievement is appended. (Contains 9 tables, 9 figures, and 93 footnotes.)[The foreword to this report was written by Gary Orfield.]