This report addresses two central questions raised by the rapidly changing economic role of American women during the 20th century. First, why have the reported wages of women remained constant at approximately 59 percent of men's wages, in spite of the enormous increase in the numbers of women who work and who presumably have been acquiring valuable market experience? Second, what accounts for the remarkable growth in the proportion of women who work? The report demonstrates that the constancy of women's relative wages at the 59 percent level is a myth. Women's wages are not 59 percent of those of men--they are even lower. But women's wages have in fact risen in response to their expanded skills, as well as their increased years of education and work experience. Throughout the 20th century, women's wages have been rising much faster than men's wages and will continue to do so into the foreseeable future. In answer to the second question, the report contends that the female labor force has grown at such a spectacular rate during this century, first of all, because of structural changes in the labor market, and more important, because of rising women's wages, which have attracted more women into the work force. (This report first discusses the issue of trends in women's wages and then summarizes findings documenting the reasons for the growth in the female labor force. An executive summary is provided.) (KC)