BOOK REVIEW : Dylan Thomas Thunders His Own Poetry : ON THE AIR WITH DYLAN THOMAS; <i> Edited by Ralph Maud</i> , New Directions, $22.95; 305 pages : STORIES AND HUMOROUS ESSAYS OF DYLAN THOMAS; <i> Performed by Dylan Thomas</i> , HarperAudio/Caedmon, 3 cassettes; $30

If Dylan Thomas had been born in 1941 instead of 1914, I suspect that he would have been a rock star instead of a lyric poet--rather like his namesake, Bob Dylan, or another Celtic bard, Van Morrison.

As it happened, the poet was tuned into the electronic mass media of his age, and Dylan Thomas made his mark on the BBC as a radio performer and personality.

Dylan Thomas’ extraordinary radio performances have long been available in recordings from Caedmon, distributed by HarperAudio, and now the fragmentary readings and recitations are given a fascinating and illuminating context in “On the Air With Dylan Thomas,” an annotated collection of scripts from the poet’s decade-long career as a broadcaster.

“It is a measure of how important radio was to the ordinary households of Britain . . . that a poetry competition launched on the air in 1930 could have elicited 11,000 entries,” says Ralph Maud, editor and annotator of this collection. “A young listener, Dylan Thomas of Swansea, aged 19, sent in ‘The Romantic Isle.’ ”

Thomas went on to become an accomplished performer and a radio personality--but not before paying his dues as a scriptwriter.

He was commissioned to write a documentary on Christopher Columbus “for translation into Portuguese for transmission to Brazil,” and he haggled over the fee for a translation of “Peer Gynt,” carping about how much more time and money Louis MacNeice was afforded for a translation of “Faust.”

“ ‘Peer Gynt’ is just as difficult to work upon as is Goethe’s ‘Faust,’ ” Thomas whined. “Why should one have to scamp through insufficient money and time?”

Still, as we learn from the detailed “Engagements Calendar” in “On the Air With Dylan Thomas,” the celebrated poet was grateful for the pounds and guineas that he scraped together by writing and delivering scripts over the BBC. As late as 1950, he agreed to write the script for a corporate documentary on Anglo-Iranian oil--and he earned 10 guineas for reading a short sidebar about his Persian sojourn.

“The night is nostalgic and sulfurous,” he rhapsodizes, making poetry almost despite himself. Thomas was famous for his literary, romantic and alcoholic excesses--indeed, he is plainly drunk in one recording of the charming but canned speech that preceded his public readings--but we are given a different impression of Thomas as a radio performer: “He was never late, he was never drunk; and he never did a bad job,” recalled one of his radio producers.

MacNeice himself characterized the thundering and resonant “organ voice” of Thomas as “a godsend to radio,” and--as one critic put it--he was not too vain to engage in “a very good and slightly malicious imitation of himself.”

Performances of several of the scripts reproduced here can be found in the 16 Thomas recordings that are available from HarperAudio/Caedmon. One recording--”Stories and Humorous Essays of Dylan Thomas”--includes some of the most haunting and hilarious scripts from the book: “Return Journey,” “Holiday Memory,” “A Visit to America” and several others.

As the recordings will demonstrate, the experience of listening to Thomas, especially when he is reciting his own poems, is rather like listening to a Bach fugue.

Thomas was brilliant at performing and explaining his own work--and the HarperAudio catalogue is weighted toward the readings of his own poetry. But he was perfectly willing to retail his own childhood memories over the airwaves, and even the most pedestrian of his “talks” achieve a certain grandeur of language and winning lyricism in delivery.

Here, as in his poems, Thomas uses noun lists and verb clusters and the pile-up of adjectives to produce a strikingly vigorous kind of poetry within the framework of his “talks.” Thus, when invited to give a New Year discourse on “The Crumbs of One Man’s Year” for a quick 20 guineas, he still managed to work himself up into a song:

“Of what has gone I know only shilly-shally snatches and freckled plaids, flecks and dabs, dazzle and froth; a simple second caught in coursing snow-light, an instant, gay or sorry, struck motionless in the curve of flight like a bird or a scythe; the spindrift leaf and stray-paper whirl, canter, quarrel, and people-chase of everybody’s street . . . . “