Knopf also published many American authors, including Conrad Aiken, James Baldwin, James M. Cain, Theodore Dreiser, Shirley Ann Grau, Dashiell Hammett, Langston Hughes, Vachel Lindsay, H.L. Mencken, George Jean Nathan, John Updike, and Knopf's own favorite, Willa Cather. From 1924 to 1934, he published the famous literary magazine founded by Mencken and Nathan, "The American Mercury". He often developed a personal friendship with his authors. Knopf's personal interest in the fields of history, sociology, and science led to close friendships in the academic community with such noted historians as Richard Hofstadter, Arthur Schlesinger, Jr., and Samuel Eliot Morison. A prominent Republican until Watergate, Knopf often drew legislators into lengthy correspondence by mail. He was also a member of the Peabody Awards Board of Jurors from 1940 to 1946.