The most remarkable trend in the U.S. labor force over the past 3 decades has been the entrance of more and more mothers of young children. In 1985, a total of 54 percent of the women with children under 6 years of age were working--four times the 1950 level. This report summarizes recent trends in labor force participation and outlines some of the obstacles faced by working mothers as they attempt to juggle job and family responsibilities. It shows that the lack of affordable child care is probably preventing many poorly educated and low-income mothers from working at all, when they are the women who need jobs the most. Discussion focuses on (1) why more women are working; (2) documenting the trends; (3) combining family and jobs; (4) balancing personal and professional lives; (5) caring for children at work; (6) characteristics of the young mother, the delayed childbearer, the unmarried mother, and the young single mother; (7) child care problems; (8) actual child care choices working mothers make; (9) the increasing demand for child care services; (10) the child care industry; (11) public policy issues; and (12) the outlook for the future. The report is illustrated with black and white photographs and color charts. (RH)