This paper discusses five themes related to the formation and functioning of stepfamilies. The first section examines how demographic trends, particularly changing marriage and remarriage rates and rising levels of cohabitation, are affecting post-marital family arrangements. The second section looks at the creation of new forms of kinship associated with remarriage and cohabitation. The third and fourth parts of the paper explore issues related to the social organization of stepfamilies and the consequences for children. The final section of the paper takes up the question of whether and why remarried persons are at higher risk of divorce. We discuss some implications of research for public policy and current theoretical debates about the status of the American family.