An American lawyer and anthropologist, he spent years working and living with the Iroquois*, most notably the Seneca. He used his legal training to help protect the Native Americans from exploitation, defending them in Congress against the Ogden Land Company (who, as you might guess, wanted their land). Because of his work, he was adopted by the Seneca, and given the name Tayadaowuhkuh , "one who bridges the gap".

During his association with the Seneca he began studying the kinship systems*** of native Americans, becoming the first anthropologist to realize that studying kinship might be useful. He noticed that many widely separated Native American groups had the same types of kinship, and he wondered if it had some sort of meaning. To follow up on this, he sent out a questionnaire to missionaries and travelers all over the world, asking them to fill it out with information on the local kinship systems. He found that there were other kinship systems like the Iroquois' in India and elsewhere. (Today this type of kinship is still called the Iroquois kinship terminology).

His studies led him to develop a theory of cultural evolution (known as unilineal evolution), based on the idea that human cultures passed through stages of development****. He based his stages primarily on kinship, subsistence, and government, although he though that cultures would at the same time be developing in the areas of language and religion, among other things. Although he believed that some cultures were more advanced than others, he also believed that all humans had reason as the basis of thought, and in primitives were exposed to higher thinking, they could, and would, see that it was Right and Good. He also believed that human societies were still evolving -- western culture was not the end result of evolution.

He also spent time studying beavers**, and the railroads and mines of Michigan. He was also named the President of the American Association for the Advancement of Science. He was a busy guy.

He died on December 17, 1881. He left his estate to his son, with the stipulation that upon the son's decease the remainder would go to the University of Rochester to start a woman's college (which it did). His wife, Mary E. Morgan, also left her (separate) estate to the University for the same purpose when she died in 1883.

The League of the Iroquois (League of the Ho-de-no-sau-nee, or Iroquois.) (1851)
*The Indian Journals, 1859-1862 (1959)
** The American Beaver and His Works (1868)
***Systems of Consanguinity and Affinity of the Human Family (1871)
****Ancient Society, or Researches in the Lines of Human Progress from Savagery through Barbarism to Civilization (1877)
Houses and House-life of the American Aborigines (1881)