Marriage is down, cohabitation is up, and the divorce rate remains high in the United States. Further, in 1950, only 1 in 20 births were to an unmarried woman, whereas today, more than a third of American children are born outside marriage. These important demographic changes are evident in Canada, the United Kingdom, and in much of Western Europe as well. Each author in this print symposium documents the extent of these massive transformations in family life and speculates about what they mean for the future of marriage.