Lewis Henry Morgan (1818-1881) was an American lawyer and amateur scholar best known for his work on cultural evolution and Native Americans. Born in rural New York he studied law at Union College and began practicing in Rochester. He developed an interest in Native Americans and spent several years living with groups local to the area, gaining their trust and eventually being formally incorporated into their society. As a result of this experience he published several accounts of Native American life, including his famous League of the Iroquois (1851), which became one of the earliest examples of ethnography. These initial researches led him to consider more general questions of human social organization. In keeping with the general interest in social evolution common to his times, he began publishing books such as his seminal Systems of Consanguinity and Affinity (1886). His goal was to explain the wide variety of kinship systems in indigenous societies as different stages in human evolution and social development. Morgan was a prominent man who received many accolades during his lifetime. He served in the New York assembly and senate, was president of the American Association for the Advancement of Science, and was a member of the National Academy of Sciences. He died in 1881.

Morgan's legacy today is slightly schizophrenic. Karl Marx and Friedrich Engels relied on his accounts of the evolution of indigenous peoples to fill in their own account of the development of capitalist society. As a result many come to his writings from a leftist or Marxist point of view. Within the discipline of anthropology he is famous for holding an untenable evolutionary position which was attacked by famous anthropologists such as Franz Boas. At the same time, many anthropologists recognize that he was one of the first people to systematically study kinship systems.