This paper explores issues related to magnet schools and racial diversity, reviewing research on magnet schools that underscores the importance of analyzing how effective magnets are in reducing racial isolation, how these data differ across districts, and what accounts for these differential effects. The paper also includes findings from a 3-year study of magnet schools in two major urban school districts (Saint Louis, Missouri, and Cincinnati, Ohio), examining the social context of school choice in order to highlight the interplay between choice policies and efforts aimed at school desegregation. It focuses specifically on issues of social class isolation in the context of magnet school systems that are designed to address racial diversity, arguing that these persistent patterns of socioeconomic segregation can be arrested under certain conditions. The paper concludes by discussing indications that the post-busing era of desegregation and litigation signals a heavy reliance upon magnet schools and parental choice without the commitment to diversity goals that marked earlier decades of social and educational reform. (Contains approximately 41 references.) (SM)