Over the course of the last half century, family life in the West and throughout much of the developed world has been deeply shaped by what demographer Dirk van de Kaa has called the “second demographic transition.” Although this transition has not been manifested in every Western country to the same degree and in the same way, it is safe to say that almost every country in the West has witnessed rising ages at marriage, increases in cohabitation and nonmarital childbearing, higher rates of divorce, a trend towards fertility postponement, and higher rates of childlessness. These changes in family structure have been paralleled by equally dramatic changes in the family processes that take place within families. A large and growing body of research has documented the nature, causes, and consequences of this transition in the West.