The central interest of this edited collection is to examine the important but little examined trend of increased participation in paid work of older women in the United States of America (USA). Noticing the dearth of research into the topic of women working longer, the editors commissioned a series of papers which were presented at a US National Bureau of Economic Research conference. The authors sought to understand the important trend of longer working lives among American women and examine some possible causes.

Claudia Goldin and Lawrence F. Katz argue that the trend in older women's increased labour market participation is long term and consequential, and that the situation in the USA is distinctive. The increase in participation is larger and began from a higher level than in other countries, has persisted for about 30 years and disproportionately concerns full-time jobs. Important predictors are level of education, health, lifecourse labour force participation and job enjoyment. However, all older female workers are not equal. Taking an intersectional approach, Joanna N. Lahey shows how older black women's labour market participation has stagnated, despite black women having much less wealth compared to white women. While this troubling gap can be partially explained in terms of the poorer health of black women, as well as differences in occupation and industry, Lahey highlights our lack of knowledge in this important area.

The financial situation of older women might be contributing to increases in participation in paid work in late life. Annamaria Lusardi and Olivia S. Mitchell present alarming statistics showing that, in recent cohorts, debts for women approaching retirement have doubled, as well as the percentage of women holding less than US $25,000 in savings. Women appear to be deferring retirement in order to repay mortgage debt. Nicole Maestas examines the implications for Social Security income of co-ordinated retirement of married partners. Additional years of paid work up to age 70 years would increase married women's Social Security wealth sizeably, placing women on nearly equal footing with married men. However, women with larger potential gains from delaying retirement are not more likely to work longer, suggesting that the opportunity cost of forfeited earnings is not factored into retirement decisions.

Claudia Olivetti and Dana Rotz argue that changes in marital history and marital status are non-trivial drivers of the increase in older women's employment. They employ a quasi-experiment using variations across states in the timing of introduction of reforms which increase the risk of divorce. They find that among women who had a low risk of divorcing ex ante, exposure at older ages to reforms facilitating divorce decreased retirement wealth and increased the probability of full-time employment later in life. This finding is consistent with ever-divorced women working remedially. Sean Fahle and Kathleen McGarry examine the labour market implications of providing family care, finding that caring for parents and parents-in-law reduces the number of hours worked weekly and persistently decreases the probability of being in paid work. They conclude that the competing claim for women's time of the growth in family care-giving responsibilities likely depressed the trend towards longer working lives.

Maria D. Fitzpatrick finds that, in more recent cohorts, fewer college-educated women have ever worked as teachers. Since public school teachers are generally covered by defined-benefit pensions that allow early retirement, the occupational shift from teaching has contributed to longer working lives. Alexander Gelber, Adam Isen and Jae Song are similarly able to relate the increase in older women's employment to institutional factors. In a quasi-experimental design, they investigate an abrupt reduction in Social Security benefits to find a corresponding discontinuous increase in women's employment rates. Gelber, Isen and Song conclude that slowed growth in Social Security benefits has contributed to rising employment rates among older women.

The conference papers in this collection employ sophisticated quantitative modelling on longitudinal and register data. By providing a state-of-the-art evidence base of recent trends and their likely causes, the book will be useful for researchers, students and practitioners. Since the National Bureau of Economic Research by tradition avoids making policy recommendations, none are presented. Similarly, the format leads the authors to refrain from considering the wider implications of their findings for theory and practice. Almost in passing, Goldin and Katz argue for an important change to the value of paid work for women in the USA today:

Changing subjective meanings of work throughout the lifecourse are one implication of longer working lives. The stage has been set for scholars to reflect on the wider consequences of women working longer.