Cohabitation has risen dramatically in the United States in a very short time. So, too, has the amount of sociological research devoted to the topic. In the span of a bit more than a decade, family sociologists and demographers have produced a large and rich body of research, ranging from documentation of cohabitation to assessment of its various consequences and implications. I first review basic descriptive findings about cohabitation as well as common explanations for its striking increase over recent decades. I next identify the central questions motivating most of the extant research and provide an assessment of past research as a whole. Finally, I speculate about themes that will be central to future research on cohabitation and consider the implications of cohabitation for gender equality in the United States and social science research on families.

Cohabitation is now the modal path to marriage in the United States. Drawing on data from 115 in‐depth interviews with cohabitors from the working and lower middle classes, this paper explores how economics shape marital decision making. We find that cohabitors typically perceive financial issues as important for marriage, and we delineate several key themes. Whereas some social scientists speculate that cohabitors must think that marriage will change their lives in order to motivate marriage, our findings suggest that cohabitors believe marriage should occur once something has already changed—in this case, their financial status. Our results also imply that political and scientific discourse on financial problems as deterrents to marriage should be broadened beyond a focus on poor unmarried parents.

Almost all our knowledge about cohabitation in the United States rests on analysis of nationally representative, large‐scale surveys. We move beyond this work by drawing on 115 in‐depth interviews with a sample of young men and women with recent cohabitation experience. These data allow us to address two issues of central interest to family studies. First, we use our qualitative data to assess the measurement of cohabitation in surveys and the census. We find that current measurement strategies are probably underestimating cohabitation, and we may need to find new ways to measure cohabitation. Second, we employ qualitative findings to address issues relating to how we empirically model union formation. We find that the movement into cohabitation is not akin to marriage. It is often not a deliberate decision. Couples do not appear to be deciding between cohabitation and marriage; rather, their decision seems to center around whether to remain single or cohabit. These results have important implications for our analysis and understanding of cohabitation.

"We review the literature on the economic consequences of marital dissolution for women. Longitudinal studies of the effects of divorce and widowhood indicate that both types of dissolutions have negative and prolonged consequences for women's economic well-being. This is not the case for men, where marital dissolution often leads to an improved economic standard of living. Following an examination of empirical studies and measurement issues in the divorce and widowhood literatures, we describe preexisting and direct sources of women's postdissolution economic insecurity." The primary geographical focus is on the United States.

Past studies of the transition to marriage generally have relied on information about only one individual or have attempted to measure characteristics of potential spouses indirectly. Drawing on data from the two waves of the National Survey of Families and Households (NSFH), we examine the effects of economic circumstances of both partners in cohabiting unions on the transition to marriage. Focusing on both partners in a relationship affords a more direct test of the relative importance of men's versus women's economic circumstances. Our findings suggest that only the male partner's economic resources affect the transition to marriage, with positive economic situations accelerating marriage and deterring separation. Our results imply that despite trends toward egalitarian gender-role attitudes and increasing income provision among women, cohabiting men's economic circumstances carry far more weight than women's in marriage formation.