<i> The Collected Letters of Dylan Thomas, edited by Paul Ferris (Macmillan: $39.95; 1,024 pp.) </i>

During a certain span of literary time, the foolish popular image of the poet was the chap in long hair and velvet cape, strolling through dew and buttercups, desperately appreciative of all about him.

The later image, hardly less pervasive, is of the poet as a chain-smoking, alcoholic womanizer lurching down the road to hell with a song on his lips and a rip in his tweeds. By any name, the poet is always Dylan Thomas, most recently fictionalized by Peter De Vries and portrayed by Tom Conti in the film “Reuben Reuben.”

No serious poet since Robert Frost has had so wide a public--in large part for the life style, no doubt, yet also for the passionate intensity and relative accessibility of the poetry itself. (His recording of his prose poem, “A Child’s Christmas in Wales,” may at that command audiences as long as anything he did.)

Paul Ferris already has written a very good biography of Thomas. Now this mountainous and mesmerizing volume of “The Collected Letters of Dylan Thomas” (more than 1,000 of them, spanning 20 of the poet’s 39 years) becomes a sort of parallel biography, perhaps a shadow biography, confirming the best and worst of what we’ve been told of the man, now revealed in his own torrential flow of words.

And what words they are: wheedling, lying, seducing, whining, boasting, flattering, celebrating, apologizing, evoking, recounting his tumultuous and chaotic life and, finally and most appealingly, talking about the making of poetry.

Thomas was word-intoxicated, drunk on the power of language before he came upon more corrosive beverages. Richard Burton used to speak of the gift of spoken language as having a bell in every tooth. Thomas had that gift, and bells on his fingers as well.

‘Dylan Thomas’

Continued from First Page Just why the gift of language should have been visited upon Thomas so early and so strongly is no clearer with him than with any great writer, though his father taught English in the good local school, and Thomas grew up immersed in literature.

In his introduction, carefully balanced between unquestioned sympathy and unblinking detachment, Ferris says Thomas was a precocious and self-centered child, thought to be weakly, and over-protected by a doting mother. In seaport Swansea, Thomas perceived his destiny early.

“Thomas made everything subservient to his need to be, and to live as, a Poet with a capital P,” Ferris writes. The trouble was, “Thomas laid it on thick. . . . Dylan Marlais Thomas, born into provincialdom, mad with words, beating on the gates of fame, and doing it all in public .”

This is exactly the portrait that emerges from the letters, of the artist as a man to whom the world owes a few quid till payday. “The majority of literature is the outcome of ill man,” he writes to a Welsh friend, Trevor Hughes, in 1933; “I am always very ill.”

The most revealing block of letters within the volume also begins in 1933. They are the poet’s pages-long and analytical letters to another young poet, Pamela Hansford Johnson, later a novelist and the wife of C. P. Snow.

She wrote Thomas in praise of one of his earliest published poems. It led to a kind of postal flirtation that evidently became a more serious relationship when Thomas finally made his way to London. You detect, as the late Lady Snow must have, Thomas as the long-distance courtier working his wiles. Yet the real passion of the young poet, who might compromise everything else but never his work, also is inescapably present.

“There must be no compromise,” he cries in one of the first letters to her; “There is always only the one right word: Use it, despite its foul or merely ludicrous associations.” The poet, Thomas told her, “is a law unto himself, and his greatness or smallness rises or falls by that. . . . I do not want to express only what other people have felt; I want to rip something away and show what they have never seen.”

When an editor called his work facile, Thomas indignantly told Johnson, “I write at the speed of two lines an hour. I have written hundreds of poems, and each one has taken me a great many painful, brain-racking and sweaty hours.”

He was occasionally sharply critical of Johnson’s work, though he said, “You have nearly everything that contributes to the makeup of an individual, original and satisfying poet.” The nearly may have given her momentary pause, but he absolved her of “the jimjackery and jugglebuggery of the bad and pretentious versifier.”

The (few) years go by; Thomas is increasingly published and recognized. Stephen Spender writes a fan letter and Thomas a fawning reply. He dismisses Edith Sitwell’s poems in a letter to someone else but later shamelessly solicits her support and receives it. The friendship was broken off and, in 1946, he wrote her in hope of restoring it (she had praised his work again).

There must have been, Thomas said, “some minor (oh, I hope so, minor) beastliness of mine, presumption, conceit, gaucherie, seeming-ingratitude, foul manner, callow pretension, or worse; yes, indeed, far worse” that interrupted their association. “If my apology, true as my love of your Song of the Cold, reads to you as stiltedly as, quickly writing, it sounds to me, I’m sorry again. . . .” The letter worked; she became a helpful friend once more.

Increasingly, money and not art is the theme of Thomas’ letters. “Regular lack of money flows in for us still,” he writes to Veronica Sibthorp, a sometime lover, in 1939; “We are still with nothing but arrogance, guile and hope. I’m just about to pawn, for debts and the demon alcohol, a silver christening present. . . .”

His patient agent, David Higham, bears the brunt of the importunings. “Can you get that hundred pounds at once and send it to my bank. . . . In about two days’ time, unless they get a cheque, they will return those damned cheques and bugger us up here for all time. . . . QUICKLY PLEASE.”

Thomas was being published, although advances and sales were modest. He wrote radio and television scripts for the BBC and gave talks and readings (although the corporation, weary of his unreliability, eventually began to use him less). He wrote film scripts and, fatefully, in 1950 flew to New York for his first series of readings in the United States. They became legendary blurs of wine, women and recited song.

One of the several remarkable things about the letters is that beyond all the wheedlings, and all the often-ingenious excuses for manuscripts not delivered on time, appointments not kept, cancellations not made--all the social debris of a disordered life--Thomas is also candid, at least to a degree, about his failings. “Oh helpless baboon,” he wrote in 1949.

Yet the real and deepening darkness was between the lines. The boozing was even worse than he admitted it was, and the fears were of more than debt. He had abused his marriage to Caitlin, but to the end of his brief life, his letters to her are outpourings of love that seem too frenzied to be glib and calculated. What you sense is that he knew too well she was his last anchor, and the rope was dangerously frayed.

In the last letter to Caitlin printed here, written in Massachusetts in May, 1953, Thomas wrote, “You are with me always, Cat, as God is with the devout; other people around me are lousy with their personal interests, are unhappy and lost, but I am certain in my body and my heart and that makes all the miraculous difference. I’m certain that we are together; I am sure that I love you. . . . People here know that. . . . They can see the love for you around me.”

The Thomas who made that last American trip, looking for an escape from his inescapable realities, was, Ferris writes, “burdened by debts and broken promises to publishers, but most of all desolated by what he feared was a decline of creative powers.”

The book’s last item is a wire to Ellen Stevenson in Chicago, agreeing to do “Under Milk Wood” there, “but not without cash.”

A doctor in New York gave him a shot of morphine to relieve his alcoholic symptoms. He went into a coma on Nov. 5, 1953, and died four days later.

Closing the book, with its star-burst splurges of wonderful language and then its gloomy chronicle of the dying of the light, the reader is moved to reread the poems, to be reminded and reassured that out of posing and the posturing, and despite all the rituals of self-destruction and that playing of the Poet with a capital P, the poetry was written and is magical.

As Ferris suggests, Thomas the wild man threatened in his last years to overshadow the achievements, and certainly the reputation, of Thomas the poet. But Ferris, in this outstanding work of discovery, annotation and interpretation, has reconfirmed that if Thomas was the wild man, he was indeed the serious and extraordinarily gifted poet, one of the best of our time.