In her introduction, Bonnie Costello writes: On July 9, 1959, T. S. Eliot wrote to Marianne Moore: "One of the books which obviously must in the fullness of time be published . . . will be the Letters of Marianne Moore."  We are pleased to fulfill his prediction. Marianne Moore's correspondence makes up the largest and most broadly significant collection of any modern poet. It documents the first two-thirds of this century, reflecting shifts from Victorian to modernist culture, the experience of the two world wars, the Depression and postwar prosperity, and the changing face of the arts in America and Europe. Moore wrote letters daily for most of her life--long, intense letters to friends and family; shorter, but always distinctive letters to an ever-widening circle of acquaintances and fans. At the height of her celebrity, she would occasionally write as many as fifty letters a day. Both Moore and her correspondents appreciated the value of their exchange, so that an extraordinary number of letters, approximately thirty thousand, have been preserved . . . It is Moore's poetry that draws us to her letters, of course. But in making this selection we have tried to present the life and mind of a woman whose interests extended to all the arts, to religion, politics, and psychology, to fashion, sports, and the domestic arts, moving freely between high culture and popular culture, and whose family and friendships remained as important as her professional life. Moore's correspondence is unique in the extent of its extraliterary interests and passionate engagement with the world at large. From her college adventures, her travels, and the flurry of her artistic and social activities, there seems to have been no lull. What has struck us most in reading through Moore's letters is the vitality and fullness of the long life they record.