It is of course as a poet of major stature that John Keats belongs among the literary figures of English Romanticism; but his importance as a prose writer is hardly less evident. That is so almost entirely on the strength of his remarkable letters, some 240 of which have been preserved either in the author's hand or as transcriptions from originals no longer extant. Keats penned his letters hastily; they represent in most cases his spontaneous and passing thoughts on life, poetry, and his personal affairs and affections expressed to close friends, fellow artists of his acquaintance, members of his family, and the young woman with whom he was in love near the end of his short and ill-starred life. None of these letters was written with any eye to that eventual fame Keats so ardently wished for his poems; yet to many readers they constitute an indispensable human...