This chapter shows how to account for the steady increase both in women's employment opportunities and in women's willingness to go to work. The best way to describe women's participation in the labor force from the late 1880s to the present is as a slow revolution, but a revolution nonetheless. Not all women entered or stayed in the labor force for the same reason or for the same amount of time. During the pre-World War II period of gradually increasing employment for women, the one sector in which women were not finding jobs was in large-product manufacturing. Protective legislation did indeed protect women, but it was also used to lock women out of better-paying jobs, particularly in manufacturing. How is it that so many women came into the workforce over a sixty-year period and that there were jobs for them to fill? In many ways, women's increased labor force participation was a matter of simple economics.