A major new study of the role of women in the labor market of Industrial Revolution Britain. It is well known that men and women usually worked in different occupations, and that women earned lower wages than men. These differences are usually attributed to custom but Joyce Burnette here demonstrates instead that gender differences in occupations and wages were instead largely driven by market forces. Her findings reveal that rather than harming women competition actually helped them by eroding the power that male workers needed to restrict female employment and minimizing the gender wage gap by sorting women into the least strength-intensive occupations. Where the strength requirements of an occupation made women less productive than men, occupational segregation maximized both economic efficiency and female incomes. She shows that women's wages were then market wages rather than customary and the gender wage gap resulted from actual differences in productivity.