Arthur Meier Schlesinger, Jr., was a leading authority on the history of the United States. Schlesinger was born in Columbus, Ohio, in 1917. His father, Arthur Meier Schlesinger, Sr., was a prominent historian of the United States. His son also became an American historian. Arthur Schlesinger, Jr. graduated from Harvard University in 1938. Schlesinger published his first book, his Harvard University honors thesis, in 1939. During World War II he serving in the Office of War Information from 1942 to 1943 and in the Office of Strategic Services from 1943 to 1945. He continued to research and write while serving his country. In 1945, he published *The Age of Jackson*. The book won the Pulitzer Prize. In 1946, Schlesinger became a professor at Harvard University. He held the position until 1961. Schlesinger's liberal political and social views heavily influenced his books and articles. He emerged as one of the most respected and influential historians of the twentieth century. He also played an active role in politics. During the administration of President John F. Kennedy he served as a campaign advisor and later became Kennedy's Special Assistant for Latin American Affairs. With President Kennedy's assassination in November 1963, Schlesinger returned to academic life. He wrote a study of Kennedy's administration called *A Thousand Days*. It won the Pulitzer Prize for biography in 1965. Schlesinger became a professor at the City University of New York Graduate Center in 1966. He concluded his teaching career in 1994. After retiring, Schlesinger continued to write books. Schlesinger died on February 28, 2007 from a heart attack.