Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Lewis Henry Morgan (November 21, 1818 December 17, 1881) was a pioneering American anthropologist and social theorist, and one of the greatest social scientists of the nineteenth century in the United States. He is best known for his work on kinship and social structure, his theories of social evolution, and his ethnography of the Iroquois. Due to his study of kinship, Morgan was an early proponent of the theory that the indigenous peoples of the Americas had migrated from Asia in ancient times. His social theories influenced later Leftist theorists. Morgan is the only American social theorist to be cited by Charles Darwin, Karl Marx and Sigmund Freud.