One of the most influential American poets of the twentieth century, Robert Lowell was also a prolific letter-writer who corresponded with some of the most remarkable writers and thinkers of his day, including Elizabeth Bishop, Edmund Wilson, Robert Kennedy, Ezra Pound, William Carlos Williams, William Empson, T. S. Eliot, Robert Frost and Marianne Moore. These letters document the transformation of Lowell's work over the course of his career; the development of his reading habits; the germination of his moral beliefs (he famously opposed the WWII draft in a personal letter to President Roosevelt and was jailed as a conscientious objector); his engagement with politics and the anti-war movement of the 1960s. They also illuminate another side of the intimate life that was the subject of so many of his poems: his deep friendships with other writers; the manic-depressive illness he struggled to endure and understand; and his marriages to three prose writers, Jean Stafford, Elizabeth Hardwick and Caroline Blackwood.