Sex differences abound in labor markets. In the United States three differences in particular have attracted the most attention: the earnings gap, occupational segregation, and the greater responsibility of women for child care and housework, and consequential lower participation in the labor market. This volume brings together David Neumark’s work of the past fifteen years: in it he tries to understand and analyze the relative importance of family economic decision-making and sex discrimination in generating sex differences in labor markets. Neumark’s research covers three main levels of inquiry. The first studies non-discriminatory sources of sex differences in labor markets; the second grapples with the problem of sex discrimination; while the third evaluates policies to combat and reduce sex differences in labor markets.