James Hadley Billington (born June 1, 1929) is an American academic and author who taught history at Harvard and Princeton before serving for 42 years as CEO of four federal cultural institutions. He served as the 13th Librarian of Congress after being nominated as 13th by President Ronald Reagan in 1987, and his appointment was approved unanimously by the U.S. Senate. He retired as Librarian on September 30, 2015.