Lewis Henry Morgan 
Ancient Society [EPUB ebook] 
Or, Researches in the Lines of Human Progress from Savagery, through Barbarism to Civilization

Ancient Society is a book by the American anthropologist Lewis H. Morgan. Building on the data about kinship and social organization presented in his 1871 ‘Systems of Consanguinity and Affinity of the Human Family, ‘ Morgan develops a theory of the three stages of human progress — from Savagery through Barbarism to Civilization.