This review-essay presents an overview of Malcolm Cowley's life as a professional man of letters. A poet at the beginning, Cowley became best known for books about twentieth-century literary history, enlivened by incisive personal portraits of its practitioners. As a writer and editor, he played a crucial role in establishing and advancing the careers of contemporaries Hemingway, Faulkner, and Fitzgerald, and of younger writers Cheever and Kerouac. During the 1930s and stretching into the next decade, Cowley was involved in the political wars as a fervent left-winger supporting communist causes, a passion he came to regret. These subjects emerge vividly in Hans Bak's edition of Cowley's letters, sent to a wide array of well-known poets and prose writers. The book, with a first-rate introduction by son Robert Cowley and periodic commentaries by Bak, reads like a biography in the making of this important and undervalued figure in American literary history.