The decline in the employment-population ratios for men and women over the period 2000-2007 prior to the Great Recession represents an historic turnaround in the evolution of U.S. employment. The decline is disproportionately concentrated among the less educated and younger groups within the male and female populations and, for women, disproportionately concentrated among the unmarried and those without children. About half of men's decline can be explained by declines in wage rates and by changes in nonlabor income and family structure influences, but the decline among women is more difficult to explain and requires distinguishing between married and unmarried women and those with and without children, who have each experienced quite different wage and employment trends. Neither taxes nor transfers appear likely to explain the employment declines, with the possible exception of the Supplemental Nutrition Assistance Program. Other influences such as the minimum wage or health factors do not appear to play a role, but increases in incarceration could have contributed to the decline among men.