A historical and critical survey of evolutionary thought that traces ideas from ancient Greek speculation through Linnaeus, Lamarck, Darwin, Weismann, and de Vries. It outlines biological mechanisms such as natural selection, heredity, and mutation, contrasts competing scientific explanations, and explores how evolutionary concepts have been applied to social theory. The text compares perspectives on cooperation and competition, debating mutual aid, the social organism, and individualism, responds to contemporary critics, and reflects on the broader implications of evolutionary reasoning for notions of civilization.