An attorney by profession, Lewis Henry Morgan became an anthropologist and ethnologist, noted for his comprehensive theory of social revolution. He was born near Aurora, New York, on November 21, 1818, and graduated from Union College in Schenectady in 1840. He read for the law and opened an office in Rochester in 1844. Although Morgan concentrated on his law duties, he also became interested in the Iroquois people of western New York State. This interest grew into a lifelong championship of native Americans against white oppressors. Morgan began an exhaustive study of the Iroquois Confederation, especially the Seneca tribe, which adopted him in 1846. He surveyed their history, social organizations, and material culture, culminating in his 1851 publication League of the Ho-de-no-sau-nee, or Iroquois. It is considered to be one of the earliest objective ethnographic works.

Between his law practice and investments, Morgan accumulated a small fortune. In 1856, he attended a meeting of the...