IN A VIOLENT swing entirely typical of his tempestuous personality, T.H. White once described L.J. Potts, his Cambridge tutor, as someone he "disliked to the point of rage for about a year," but later came to regard as "the most noble gentleman I have ever met" and "the great literary influence in my life." Collected here for the first time, the 30-year correspondence between White and Potts records a student-teacher relationship of such special, near-magical intensity that it parallels the Merlyn-Arthur relationship in White's masterpiece, The Once and Future King.

Admirers of White's ever-popular tetralogy will be especially happy with these letters, for they document in intricate detail the book's conception, writing, and strenuous revision. The first we hear of the project is in a 1938 letter where White mentions the launching of a new book: "I think it is one of my better books, so probably nobody else will. . . . It is not a satire. Indeed, I am afraid it is rather warm-hearted."

It is to be loosely based on Malory's Morte d'Arthur, which White gleefully admits to having just read for the first time ("Naturally I did not read Malory when writing the thesis on him"). To his surprise, White discovered that Malory's characters were drawn with consummate vividness and realism: "Arthur, Lancelot and even Galahad were really glorious people -- not pre-raphaelite prigs. . . . I am beginning to run out of reasons for writing to you, and that reminds me that it is decent of me to write you at all."

A year and a half later, after Potts had blue-penciled numerous passages he judged to be marred by cheap anachronisms, "determined facetiousness," and barely hidden diatribes against White's hated "vampire" mother (who became Morgause the witch), White began extensive revisions: "You can't think what agony it is to re-write a book. The old part rises up like Banquo and stands between you and the page." But gradually Potts, who was virtually the first person to recognize White's talent for fiction, began giving cautious praise and encouragement: "I reserve judgement of Lancelot . . . But your idea of Guenever is right -- She is obviously a most formidable woman. . . . a sort of Queen Victoria. . . . Do you get Sir Dinadan in? He is a most delightful character -- perhaps the one really nice person in the whole business. For you know they are a grim lot, like real people."

According to Sylvia Townsend Warner, White's biographer, this correspondence is "better than the letters to (David) Garnett, because they are without the desire to impress." Included in this collection are White's letters to Potts' wife Mary, which are equally spirited and eccentric. In one of these he thanks Mary for a piccolo she sent him and describes himself playing it "sitting in a rock pool 1/2 mile out to sea, with no clothes on, like a debauched merman."

This book covers an enormous range of subjects. A novelist, falconer, adventurer, educator, and natural historian, White was an intense, complicated man who insisted, as editor Francois Gallix writes in his superb notes, on living out several personae at once "in the course of a lifelong effort to sustain as high a version of any state as possible." In addition to erudite material on these careers, the letters offer commentary on White's psychoanalysis, his empathy with children (documented in an enchanting correspondence with Potts' son William), his book reviews for the Times Literary Supplement (the "malevolent rag" he never quite forgave for giving The Once and Future King a frivolous review), and his touching friendship with a deaf-and-blind lady named Puck. White could write with intuitive brilliance on subjects he knew little about, as is evidenced by his prophetic assessment of Gilbert and Sullivan: "Everybody knows the official attitude of the musical eggheads who sneer at them because, 'it is not good music.' . . . The construction of these Gilbertian jokes (is) so frivolously, Aristotelianly perfect that they entrance me, and I contend that just as the words are a happy skit on tragedy, so is the music a pleasant skit on opera."

Despite their exuberance, many of the letters communicate an underlying sadness, particularly the ones which candidly document his never-ending string of botched love affairs. White preferred to live with cats, dogs, hawks, toads, and grass snakes ("a frightful ordeal for the maid who cleaned his room") instead of people. This peculiar way of living took a severe toll in loneliness and bouts with alcoholism, but it also generated White's celebrated descriptions of animals, who come alive as charmingly in these letters as in White's novels or his Book of Beasts. "We have got a cat," he writes Mary, "which is the first cat I ever got on with. The cat and I are both sadists, and we recognize this in each other, and don't mind. . . . I pull its tail whenever I see it, and it bites me whenever it sees me, and we both don't care a fig." On a darker note, he writes of the terrible grief he experienced at the death of his red setter Brownie, "a mother, child and mistress to me for fourteen years . . . the only perfection I have ever known."

The other major chronicle of grief here is the death of Potts in 1960, a sad counterpoint to White's final surge to fame with the opening of Camelot, the Broadway version of The Once and Future King. White's final letters to Mary are a moving, faltering, attempt to cheer them both up -- the only letters in the collection that are not convincing.

White's own death came two years later on board a ship sailing from New York to Greece. As Gallix points out, White died much as he lived, "on his way to new adventures, and alone." Both the adventure and the loneliness -- the essential White -- are beautifully captured in these letters to his magus and father figure. Potts was on target, as usual, when he told his favorite student: "The one character you can dramatise perfectly is yourself."