Lewis Henry Morgan was a pioneering American anthropologist and social theorist who worked as a railroad lawyer. He is best known for his work on kinship and social structure, his theories of social evolution, and his ethnography of the Iroquois. Interested in what holds societies together, he proposed the concept that the earliest human domestic institution was the matrilineal clan, not the patriarchal family.

In anthropology, kinship is the web of social relationships that form an important part of the lives of all humans in all societies, although its exact meanings even within this discipline are often debated. Anthropologist Robin Fox says that the study of kinship is the study of what humans do with these basic facts of life – mating, gestation, parenthood, socialization, siblingship etc. Human society is unique, he argues, in that we are "working with the same raw material as exists in the animal world, but [we] can conceptualize and categorize it to serve social ends." These social ends include the socialization of children and the formation of basic economic, political and religious groups.