This article provides an overview of America's urban population based on the 2000 Census and the implications of increasing cultural diversity for urban public schools. It addresses three basic questions: 1. What does America's population look like at the beginning of the 21st century? 2. What challenges do children and their families face in this time of rapid demographic change? 3. What role can communities play in helping culturally diverse children do well in school? Current demographic trends indicate that ethnic minorities, especially immigrant groups, not only grow rapidly, but are also increasingly concentrated in urban areas, and that the level of residential segregation by race and class in 2000 remains as high as in 1990. Demographic shifts create new challenges for the education of racial minority and immigrant children. At issue is not whether children are able to advance beyond their parents' status. Many do so because their parents are insufficiently educated and are struggling at the society's bottom, but whether they can move up to and secure a position in the ranks of the American middle class. Research has shown that certain children living in the inner city are able to do well, despite adversarial conditions. A key difference is the availability and accessibility of community-based resources, such as after-school tutoring and other educationally oriented programs, that serve children.