Over the last 25 years, women in the advanced industrial world have streamed into the formal labor force in record numbers. But rather than working with men, they typically labor in female "occupational ghettos" and hypersegregated firms. This turn of events raises several questions: Why has occupational segregation persisted in such extreme form even as other forms of gender inequality have lessened? Why is segregation especially extreme in precisely those countries, such as Sweden, that are committed to egalitarian reform and family-friendly policies? And why do some forms of segregation persist even when they disadvantage men? The authors resolve these puzzles by revealing two deep structures underlying contemporary segregation: a horizontal dynamic that segregates men and women into the manual and nonmanual sectors, and a vertical dynamic that allocates to men the most desirable occupations within each sector but not across them. Although egalitarian policies delegitimate vertical forms of segregation, this desegregating effect is muted and ultimately offset because the logic of egalitarian policy and postindustrial economic development allows horizontal forms of segregation to persist and even grow. Studies in Social Inequality