This brief draws upon the five-year evaluation study of the San Diego Urban Systemic Project (USP) that Inverness Research Associates conducted from 2001 to 2006. The intended audiences for this brief are those interested in investing in, supporting, or designing initiatives that aim to improve math and science education in large urban districts. These include reform leaders, funders, science and mathematics educators, district administrators, school, and general public. The San Diego USP was one of approximately 30 projects funded by the National Science Foundation (NSF) through its Urban Systemic Initiative, an initiative which focused on enhancing mathematics and science programs in urban school systems with large numbers of children living in poverty. The NSF encouraged the USP districts to pursue a systemic approach, to work in multiple dimensions of improvement simultaneously, including curricula, assessment, professional development, policy and resources. San Diego Unified School District's USP sought to create system enhancements in each of these dimensions that would yield better teaching, and, as a result, overall improved student learning in mathematics and science (K-12). This report looks at San Diego as a particular instantiation of the systemic approach to educational improvement, and offers the reader key lessons learned that can be applied to other similar change efforts. In summary, the experience of the San Diego USP suggests that foundations should conceptualize their grants to large urban districts as value-added investments, aimed at adding value to existing efforts, rather than expecting their funded work to single-handedly produce unrealistic outcomes.