Robert Lowell (March 1, 1917–September 12, 1977), born Robert Traill Spence Lowell, IV, was an American poet whose works, confessional in nature, engaged with the questions of history and probed the dark recesses of the self. He is generally considered to be among the greatest American poets of the twentieth century. Lowell reached wide acclaim for his 1946 book, Lord Weary's Castle, which included ten poems slightly revised from his earlier Land of Unlikeness, and thirty new poems.