YOUR PRAYERWHEEL was oiled at the exact mo-

ment," Sylvia Townsend Warner wrote in gratitude to one friend and, to another: "to think that in all the sermons that have been preached about the Prodigal Son no one has yet mentioned that his final, his crowning act of prodigality, was to go home."

These lines come from her letters. To waste no time in getting back to them, let me for a moment cite the simultaneously published volume with which they make an unwieldy package. Miss Warner's poems have so little in common with her prose as to make them seem like sports occurring in the grip of schizophrenic dilemma. To account for their archaicism and imitativeness, one can only suggest that poetry was for her a rustic pre-Georgian uniform she could put on at will. But not without hazard: The garment seemed not only to dictate her attitudes but, for the sake of some outworn notion of propriety, to reduce her language to the limp meters and banal rhythms of poesy. Her true poetry is in her prose--tough and funny and studded with invigorating exactitudes. A talent as large as hers must, in its lesser manifestation, be forgiven a phase of arrested development.

Faced with the task of accounting for the substance and flavor of her endlessly engaging letters, a reviewer is tempted--first by delight and then for want of any recommendation more fair--endlessly to quote. Here is Miss Warner on American politics: "I am in a fidget about the election, too. I would be easier in my mind about Stevenson's chances, if there were some little scandal or dash of blackguard about him. People with votes develop that odd mixture of patronage and quixotism that swings them toward handicapped candidates, provided the handicap is louche or ludicrous. If Mr. Truman had been of godlike form and intellect, he would not have got in the last time. Personally, I cannot endure Eisenhower, the man is perpetually in tears . . . I think I am giving way to national prejudice, though. Public characters in this country are not supposed to weep in public, except about cricket."

On British politics: "Can you suggest any suitable aspersions to spread abroad about Mrs Thatcher?. It is idle to suggest she has unnatural relations. . . . What is needed is something socially lower: that she eats asparagus with knife and fork, or serves Instant Mash potatoes. . . . I never thought I would live to regret the suppression of Edward Heath, but now I pine to see his honest British teeth in the public press again."

On French politics: "General de Gaulle is again pictured in our newspapers, looking as usual like an embattled codfish. I wish he could be filleted, and put quietly away in a refrigerator."

She lived among dead authors with a depth of old shoe familiarity that allowed for brusqueness in judgment and promoted a kind of reckless crankiness: "How very delightful, my dear, that you are well enough to write letters, to read Dante, and to despise him. I quite agree with you--a black-hearted, cold-hearted prig. . . ." "Please don't write a life of Milton. It is such a melancholy subject, the way the English Angel, flourishing about in Italy, degenerated into a public figure, generally cross about something. There is quite enough to depress one as it is, without being reminded of Milton." ". . . it occurred to me to see how the eclipse was getting on. The sun was silver, like a moon, and very much smaller than usual, because of having its disk defined. And while I was watching, I had a rush of astronomy to the head, and realised that the round shadow on the sun was not a shadow, but the moon. There was the sun, here was me, and that was the moon between us. For a few seconds I felt myself an inhabitant of the solar system--a delightful and enlarging sensation. I daresay Thoreau felt like that all the time." "How enchanting Coleridge is from the moment one gives up expecting to admire him!"

Daughter of a house master at Harrow, Sylvia Townsend Warner was born to privilege, mainly the privilege of learning. An only child, she was given the run of her father's library where, before she was 10, she first took down the book she was reading at the time of her death nearly 75 years later: Vanity Fair. Tutored in history by her father, in French by a governess, she came to her first love, music, through the influence of Harrow's young music master--later Sir Percy Buck. Only the onset of World War I blocked her intention to journey to Vienna in order to study with Arnold Schoenberg.

In the course of the war, her ambitions as a composer and musicologist were modified when she published an article on her experiences as a worker in a munitions factory, began to write poetry in the prevailing mode of inglenook chauvinism, and became friendly with a few English literary figures. Among these was the novelist T.F. Powys, to whom a number of her letters are addressed. Through him she met Valentine Ackland, the young woman who would become her lifelong companion and the center of her emotional and domestic existence.

Intellectually, Miss Warner was, like most of her literary contemporaries, driven by the rise of fascism to the left and, for a time, all the way. As a member of the Communist Party of Great Britain, she went with Valentine to Spain during the Civil War, came to America as a Marxist-oriented delegate to a writers' conference and, at home, raised an imperious and deliberately disruptive voice at meetings sponsored by reactionary politicians. But in 1939 her literary career took a wide if not wholly abrupt turn. Curbing her polemical contributions to leftish British periodicals, she entered upon a relationship with The New Yorker that would endure for 40 years. In that time she published in its pages 144 stories and nine poems, a record of appearances there rivaling in number those of John Cheever and John O'Hara. Gathered into seven individual volumes, these, along with seven novels and a biography of T.H. White, define a career much enhanced by this collection and eventually, it is to be hoped, expanded by other letters and the publication of the still untranscribed 40 notebooks of a personal journal.

Her particular editor at The New Yorker was William Maxwell. A novelist whose distinction is at least equal to that of his subject, he has edited these letters with a deft and spare hand, apparently guided by a determination to do little more than identify Miss Warner's correspondents, clarify missing connections and otherwise let the woman speak for herself.

Letters are the most intimate form of autobiography-- the breathing, untidy, repetitive substance of a life before it is submitted to the self-protective restraint of even the most candid tellers of their own tales. In Miss Warner's case, facts about her recorded in Maxwell's pithy introduction and footnotes are mere guideposts to the career of a woman of whom David Garnett wrote: "Ideas, epigrams and paradoxes raced through her mind and poured from her mouth as though she were delirious." Fortunately, one man's notion of delirium will strike many readers of this selection as a mistaken description of a mind alive to all of its chances, and of a voice sufficiently commanding to make them good, at once and permanently.

Miss Warner is impatiently wise, both feisty and stoical. Most of her observations have to do with the "outside world" and are subject to its annoying waywardness. But many of them are based on acute self-analysis, no less in times of confounding joy than in times of anguish. She understands how inconsolable bereavement, quite like falling in love, can excommunicate its victims from even their most congenial society. She predicts, in the midst of the desolation she suffered when Valentine abandoned her for a younger companion, what will, and indeed did, see her through. "Hurrying to my old pulpit," she wrote to an unidentified friend similarly threatened, "I adjure you, I implore, say no more, think no more, about perhaps losing ( ) to some one else. To think of losing is to lose already. To consider a rival fattens an insubstantial into a real being. Since you are in the river, darling, SWIM! And if that hypothetical younger person comes into your mind, think of me. Here I am, grey as (a) badger, wrinkled as a walnut, and never a beauty at my best; but here I sit, and yonder sits the other one, who had all the cards in her hand--except one. That I was better at loving and being loved."

But the compelling interest of these letters has little to do with the ups and downs of emotional attachment, not even with Miss Warner's informed opinions and irascible judgments. The fascination lies in their continual suspense--a wonder as to how a mind in absolute control of itself and of "the wild poetry of the race" will show itself next. To read her is to glimpse what the revels of language are all about. The elegance of hers is not a veneer but a grace so pervasive that a description of a morning spent in the garden takes on Vergilian pertinence. Yet, even in the most protracted runs of elegance, comedy is the leavening ingredient, comic impulse the force that transforms a flat phrase into an apothegm or twists the soberest matter into hilarity. Of the American poet Elinor Wylie whose ghost was supposed to have turned up regularly at the MacDowell Colony in New Hampshire, she wrote to a friend: "Her ghost appeared in Peterborough, her flesh appeared in London. I don't suppose there would have been much difference to the eye. She was made of dew and silver and the filigree of autumn-worn leaves. She was as much in earnest as a child, and as instantaneously. We met at some party or other, and with no more ado she began to talk about water, its quality and behaviour, and about Shelley's assignations with it, in his life, in his poetry, in his death. As you know, she believed she was his reincarnation. Maybe she was right. He never stayed long in any one place."

Seven lonely long years after Valentine's death, and less than two before her own, Sylvia Townsend Warner wrote to American friends to say that "in this dreamlike heat I have been sorting the original Valentine & Sylvia letters for you. She is so life-like, so authentic, that she seems to be in the room with me. It is myself I cannot believe in. Was I ever like that, I think: so free, so spirited, so weathercock to every small wind. What has become of the woman? She must have been overlooked when they ended the story, when the last letters were written."

Not so.