American women in their sixties and seventies are working more now than ever. Their increased participation at older ages started in the late 1980s, before the turnaround in older men’s labor force participation and prior to the economic downturns of the 2000s. The higher labor force participation of older women is a real trend that has persisted for almost 30 years. It is, moreover, consequential and consists disproportionately of women who are working at full-time, not part-time, jobs. Many other OECD nations have also experienced an increase in the participation of older women. But few have had as large an increase as the US from as high a level. The nine essays in this volume address the reasons for the increase in the US and what the future could hold for women working longer. The essays consider factors such as expanded lifecycle participation, increased education, occupational change, changes in marriage and divorce, caregiving, retirement saving and financial literacy, and changes in Social Security generosity. One essay confronts why black women have not been working longer and another assesses data problems regarding income adequacy during the older years. These essays address a relatively new trend and they will be a starting point for any researcher or policy-minded individual interested in this fundamental change in women’s lifecycle labor force participation.