Robert Lowell, 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.

His first and second books, Land of Unlikeness (1944) and Lord Weary's Castle (for which he received a Pulitzer Prize in 1947, at the age of thirty), were influenced by his conversion from Episcopalianism to Catholicism and explored the dark side of America's Puritan legacy.

Under the influence of Allen Tate and the New Critics, he wrote rigorously formal poetry that drew praise for its exceptionally powerful handling of meter and rhyme. Lowell was politically involved—he became a conscientious objector during the Second World War and was imprisoned as a result, and actively protested against the war in Vietnam—and his personal life was full of marital and psychological turmoil. He suffered from severe episodes of manic depression, for which he was repeatedly hospitalized.

Partly in response to his frequent breakdowns, and partly due to the influence of such younger poets as W. D. Snodgrass and Allen Ginsberg, Lowell in the mid-fifties began to write more directly from personal experience, and loosened his adherence to traditional meter and form. The result was a watershed collection, Life Studies (1959), which forever changed the landscape of modern poetry, much as Eliot's The Waste Land had three decades before.

Considered by many to be the most important poet in English of the second half of the twentieth century, Lowell continued to develop his work with sometimes uneven results, all along defining the restless center of American poetry, until his sudden death from a heart attack at age 60. Robert Lowell served as a Chancellor of The Academy of American Poets from 1962 until his death in 1977.