William Graham Sumner (October 30, 1840 - April 12, 1910) was a classical liberal (now a branch of "libertarianism" in American political philosophy) American social scientist. He taught social sciences at Yale, where he held the nation's first professorship in sociology. He was one of the most influential teachers at Yale or any major schools. Sumner was a polymath with numerous books and essays on American history, economic history, political theory, sociology, and anthropology. He supported laissez-faire economics, free markets, and the gold standard. He adopted the term "ethnocentrism" to identify the roots of imperialism, which he strongly opposed. He was a spokesman against imperialism and in favor of the "forgotten man" of the middle class, a term he coined. He had a long-term influence on conservatism in the United States.Sumner wrote an autobiographical sketch for the fourth of the histories of the Class of 1863 Yale College. In 1925, Rev. Harris E. Starr, class of 1910 Yale Department of Theology, published the first full length biography of Sumner. A second full length biography by Bruce Curtis was published in 1981. Other authors have included biographical information about Sumner as shown by citations in this "Biography" section.Sumner was born in Paterson, New Jersey, on October 30, 1840. His father, Thomas Sumner, was born in England and immigrated to the United States in 1836. His mother, Sarah Graham, was also born in England. She was brought to the United States in 1825 by her parents. Sumner's mother died when he was eight.