This document discusses definitions of the family and different types of family structures. It begins by defining the family as a social unit that is usually linked by blood, marriage, cohabitation, child-rearing responsibilities and economic cooperation. It then describes nuclear families, extended families, blended families, and binuclear families. The document also covers kinship networks, marriage, courtship and mate selection, functions of the family, and alternative family forms including cohabitation and single-parent households. It discusses perspectives on the family from functionalism, conflict theory, and symbolic interactionism.