Just as dynamic changes are occurring in the size, composition, and health status of the aging population, the American family is also undergoing transformations that will affectthe ability of families to provide care for their elder members. In this chapter the term family is used in its broadest sense to include the many varieties of family structure in which related and nonrelated individuals live together and function as family to each other, both instrumentally and emotionally. Only such a broad definition accurately captures how the care of older people occurs in a “family sense.”