This paper examines recent research on grandparents in American society. The review begins with a description of two key demographic changes that have altered the nature of grandparenthood: increased life expectancy and new rhythms in the family life cycle. Variations in the grandparent role are then discussed, including the development of typologies, the ambiguous nature and large variance in form and function, and social and legal rights and obligations. Research on the roles of grandparents with young grandchildren, including the impact of gaps in the nuclear family, such as divorce, death, or incarceration is summarized. The increasing role of grandmothers as surrogate parents and the accompanying problems are also discussed. The paper highlights the impact of grandparents on their grandchildren's lives, and the discrepant findings regarding the relationship of grandparents and adult grandchildren are also noted. The role played by the parental generation in mediating the grandparent-grandchild relationship is then described, including the impact on emotional closeness, the effect of divorce in the parent generation and the role of custody, and issues related to grandparent visitation and legal rights. Factors related to grandparents' psychological well-being, including satisfaction with the role and its relationship to broader life issues and the impact of gender, ethnicity, and social class on the grandparent role is also examined. The paper concludes with brief implications the great-grandparent role. Contains a 135-item bibliography. (KB)