Roman Catholic monk, poet, and prolific writer on spiritual and social themes, one of the most important American Roman Catholic writers of the 20th century.

Merton's early education was in England and France; after a year at the University of Cambridge, he entered Columbia University, New York City, where he earned B.A. (1938) and M.A. (1939) degrees. After teaching English at Columbia (1938–39) and at St. Bonaventure University (1939–41) near Olean, New York, he entered the Trappist Abbey of Gethsemani near Louisville, Kentucky. He was ordained priest in 1949.

Merton's first published works were collections of poems—Thirty Poems (1944), A Man in the Divided Sea (1946), and Figures for an Apocalypse (1948). With the publication of the autobiographical Seven Storey Mountain (1948), he gained an international reputation. His early works are strictly spiritual, but his writings of the early 1960s tend toward social criticism, and many of his later works reveal an insight into Oriental philosophy and mysticism unusual in a Westerner. He was electrocuted by a faulty wire during an international monastic convention in Thailand.

Merton's only novel, My Argument with the Gestapo, written in 1941, was published posthumously in 1969. His other writings include The Waters of Siloe (1949), a history of the Trappists (Trappist); Seeds of Contemplation (1949); The Living Bread (1956), a meditation on the Eucharist; and further posthumous publications, including the collection of essays entitled Contemplation in a World of Action (1971) and The Asian Journal of Thomas Merton (1973). Seven volumes of his private journals and several volumes of his correspondence have been published.