ON BROADWAY there are avents and then there are EVENTS. And seldom has there been such an EVENT as the opening on April 7, 1949, of "South Pacific."

Rodgers and Hammerstein were at peak, with "Oklahoma" and "Carousel" behind them.Mary Martin had signed on, fresh from playing Annie Oakley, Ezio Pinza, the era's leading bass and a consummate Don Giovanni, had agredd to cross the bridge from opera to Broadway as co-star. The source material was timely and unconventional, "Tales of the South Pacific," a set of short stories - by the then-obscure James Michener about the Pacific war - that had just won the Pulitzer prize. And the director and, as it turned out, the co'author was to be Joshua Logan, who the year before had stagged that other pacific war drama, "Mr. Roberts" Logan also was a co-producer, as was Leland Hayward.

Out-of-town reactions were ecstatic and advance sales broke all records. Some days later, the redoubtable Brroks Atkinson of The Times recalled the mood of April 7:

"Business practically stopped all over town, as the day before Christmas. Everyone was obsessed with one idea. The teller at the bank murmured wistfully over the top of a pile of bills: "I hope "South Pacific" is as good as they say it is going to be." The bank manager announced with the confidence of a thoroughly trained seer. "You're going to see a wonderful show tonight. Friends of mine saw a preview yesterday.

"Brushing aside dour affairs of state this alert and enterprising newspaper rearranged its printing schedule to get the news of the play into one edition earlier than usual. When my wife and I swept imperiously up to the Majestic Theater in the evening, the taxi driver jeered at the throng on the sidewalk: "Any of you want my autograph?" ad "South Pacific" flopped, it would have flopped like no other flop. But fortunately, on the morning after, virtually all agreed with the Atkinson verdict: "Although expectations had been fabulous, 'South Pacific' mercifully fulfilled them."

Twenty-eight years have passed, and "South Pacific" is still very much with us. A new production, like the one opening Monday night at Wolf Trap with Jane Powell and Howard Keel, is still an important event. The warmth and individuality still endure of that motley crew of incongruous characters, who were (to quote Atkinson's superb review) "inexplicably tossed together in a strange corner of the world...in the midst of the callous misery, boredom and slaughter of war."

Just as the fascination with World War II continues unabated into a generation that doesn't even remember it, so does the appeal of Nellie Forbush, Emile de Becque, Bloody Mary, Luther Billis and so on. One doesn't stop to think that today they would be in their late middle age or old age.

In a recent interview, Michener was reminded of the pessimism he had expressed in "Tales" on this point: "These men of the South Pacific...like their victories, will be remembered as long as our generation lives. After that, like the men of the Confederacy, they will become strangers. Longer and longer shadows will obscure them until their Guadalcanal sounds distant on the ear like Shiloh and Valley Forge."

Michener, now 70, acknowledges he underestimated the extent of the appeal: "You know, I have been thinking about World War II. I saw an ad last night for the movie 'A Bridge To Far' and my wife and I were talking about why that disastrous happening 33 years ago would command so wide an audience now. Obviously, there is a character to that war that sets it off from most other wars. I don't go for the argument that it is because it was a crusade. It was not a crusade.

"But World War II has a special place in our history, because as it went on we came to a point where the total society supported it, one way or another. Everything was supportive. It was a clear-cut goal that commanded the best people and the best of our society.

"But I would like to think that World War II will not achieve the lasting historical charisma of the Civil War. That was a stupendous event."

Asked how he believes the Vietnam war will be remembered, he said, "I think that in about eight or nine years a great book will come out about Vietnam from someone who served there, someone who was about 25 at that time. I think the interest in the Vietnam war is going to last for some time."

In his recent autobiography, "Josh," Logan relates how the literary source of "South Pacifc" was, by a fluke, recommended to him and co-producer Leland Heyward, "Mr. Robert" was in rehearsal,and the two men were with a group of "A Streetcar Named Desire." Kenneth MacKenna, story editor at MGM, told them, "There's a book laid in the Pacific at the same time (as 'Mr. Roberts') that we've just turned down. In fact all the movie companies passed it, but you might glean something from it - some color for 'Mr. Roberts.'"

Logan brought a copy of "Tales" and started reading it after a plane flight to Florida with Hayward. "That night, in our Miami Beach suite," Logan tells, "I flicked through the book and started to read the story called "Fo' Dolla." And I was ensnared. Logan concealed his infatuation from Hayward because he wanted to purchase the rights alone. But the crafty Hayward figured out what was going on and grabbed the book one day while Logan was asleep and started reading. By the time Logan awakened, it was going to be a Logan-Hayward purchase.

They got right on it, and agreed that "Tales" would made a musical and that "Rodgers and Hammerstein would be perfect." Sometimes later, Logan stopped Richard Rodgers at a party and told the composer, "I own a story you might make a musical of. He pulled out a little note pad and wrote in a businesslike way. T of the S.Pacific.'"

Time passed, with no word. Hayward investigated and reported back that Rodgers and Hammerstein wanted to do the show but wouldn't do it unless they "own 51 per cent to our 49 per cent, which assures tham the final say and us no say." Thus began the first of the many acrimonious exchanges that were to make "South Pacific" a bitter experience for Logan. But Logan and Heyward gave in ("Later on, I couldn't forgive myself," writes Logan) and a contract was signed.

One person, though, who certainly had nothing to be upset about was Michener. "Tales" had modest beginnings. It was his first fiction work and initially "it certainly created no storm, and contrary to the popular notion, it never even made the best-seller list. The book was born and it died. Then at the last possible moment along came the Pulitzer and then the play came along."

The problem was that the format of 18 short stories and an introduction was anathema to publishers. But the short story seemed the most effective way for Mitchener to record hsi insights and observations of "the tremendous performance of the Americans in war. Sometimes it's the right form. And it was remarkable that at my age and with my inexperience I was hit on the right form and stay with it.

"It's the only book I've ever written," says Michener, "where the sales went steadily up after the first year. And the book has achieved a certain timeless quality that I was reaching for."

The birth of "South Pacific" was not easy, and for Logan, as a result of his worsening relations with Rodgers and Hammerstein, not happy. As Mitchener says, "It was a muddy little ball game."

Initially the plan had been to limit the show to one story, "Of' Dolla'," about the beautifull native girld Liat, and the affair her mother promotes with the American Lt. Joseph Cable. The mother who sends them off for romance to Bali Hai, of course, is the foul-mouthed Bloody Mary, with her betel nuts and their juice dripping from the corners of her mouth.But as Rodgers notes in his autobiography, "Fortunately, to obtain the rights to "Fo' Dolla'," we had brought rights to the whole book." And soon Hammerstein was caught by another story, "Our Heroine," in which a middle-aged, cosmopolitan French planter (and a widower with two Eurasian children), Emile de Becque, and an ingenous American nurse from Little Rock, Nellie Forbush, fall in love.

Logan relates, "It was Oscar's great contribution to combine the two stories, making the nurse and the planter the major one." Also worked in is Michener's gripping story, "The Cave," about the coast watcher who hid in the hills and reported by radion the movements of the Japanese fleet until the Japanese hunted him down and killed him.

Nellie's part was planned from the beginning with Mary Martin in mind, though she says in her autobiography, "My Hearts Belongs," that Pinza was already signed on as de Becque when Rodgers and Hammerstein formally approached her ("I was frightened at the thought of singing with Ezio Pinza...Oh, that glorious voice!). She delayed and finally Rodgers asked her over and played some of the songs. Oddly enough it was hearing "Some Enchanted Evening" that finally convinced her. She writes, "It wasn't 'mine,' it was Ezio's, but that didn't matter . . . (I was convinced) it would be one of the memorable songs of the musical stage." And at 3 a.m. following the evening of music, Martin called Rodgers to accept.

After that the most serious threat to the show probably was a case of writer's block that struck Oscar Hammerstein as the deadline for the book approached. Rodgers called Logan with the news that after months Hammerstein, normally a fast worker, had produced only the first scene and an outline. Logan called Hammerstein at his Pennsylavania farm, and Hammerstein exclaimed, "Josh, I know absolutely nothing about Army behavior or how a sergeant talks to a general and vice vers." Hammerstein admitted he was stymied, and Logan, a wartime Army Air Force officer, drove to the farm to help out.

The two reviewed the scened and in two days had them committed to memory. And then, each assumed the characters each most identified with as they improved dialogue and their secretaries took it all down. Their wives ollated the pages on the living room floor. Within 10 days, the book of "South Pacific" was written.

Michener believes that without Logan at this point and others, "South Pacific" might never have made it: "Josh brought reason and a clear vision of what could be done."

The collaboration on the book brought on another of the bitter transactions that Logan had with Rodgers and Hammerstein. Since he had, in effect, saved the show, he asked for author's royalties (in addition to director's royalties, which unlike author's royalties, end when a run closes) and for co-billing with the two others. Hammerstein seemed amenable, but after consultation with Rodgers and their lawyers he reported to Logas, looking embarrassed, that Logan colud have equal credit on the book, but then he said that the lead-in would be "A Musical Play by Rodgers and Hammerstein" He aded, "Your name and mine will be below that but with only 60 per cent of the Rodgers and Hammerstein credit. Your director credit will be diminished to 60 per cent as well . . . and it goes without saying that you won't get anything whatsoever of the author's royalties.

Logan was flabbergasted, but he didn't take it out Hammerstein, whom he liked, because he sensed that Hammerstein was "speaking lines he had been instructed to say." After much fretting, the man who had once owned the show with Hayward agreed to the terms. Only later did he discover that when the other side's lawyers delivered the draft contract to Logan's attorney, it was accompanied by a written threat to replace Logan if he didn't sign. Fearing the consequences, the attorney and Logan's wife had concealed the threat.

The first rehearsal was in New York warli in 1949. "Mary Martin arrived at five to 10," Logan recalls, "and shortly after Pinza came in with his full conrie fo accompanist, lawyer, arrange, wife and several others. Whispers had it he had been waiting in the alley until Mary showed up, the most important must arrive list."

A the work continued, old songs were dropped and new ones replaced them. There was a song for Pinza, just before his mission into enemy territory in which Cable is killed, "Now is the Time." It seemed wrong, and in two days a substitute was written, the glowing lament for Nellie, "This Nearly Was Mine" (Martin notes with gleo her discovery while wateching Pinza practice this song that "this great basso didn't read music much better than I did"). Cable had no song to sing after he made love to Liat in the hut. The first effort, "Suddenly Lucky," was rejected by Logan as the "lightweight" for the circumstances. The composer and lyricist came up with a tune called "My Wife" that had been dropped from their show "Allegro," and, with new lyrics, it became "Younger Than Springtime."

"Suddenly Lucky," by the way, was not forgotten. Two years later, and with new words, the song becames "Getting To Know You" in "The King and I." "I'm Gonna Wash That Man Right Outa My Hair" was a late starter, too. It was Mary Martin's idea after she discovered that her shortened hair would dry in just three minutes after a shower. For that she submitted to eight onstage hair washing a week for several years.

A smash hit seemed so certainly by the time of the New York opening that the roof of the St. Regis Hotel was reserved for a proper celebration. When the earlier-editioned Times arrived, their hopes were justified. But even there Logan got the short shrift. Atkinson referred to the triumph as that of Rodgers and Hammerstein. Logan was upset and complained to a Times reporter at the party. The reporter called Atkinson and in subsequent editions the review read, "Rodgers and Hammerstein and Logan have given us..."

No doubt Logan was a bit paranoid, but the next year he was further a shaken when his name was omitted as "South Pacific" won the Pulitzer Prize, only the second musical to do so and apparently the only story ever to win Pulitzers in prose form and later in a stage adaptation.

Relations became so strained that Logan turned down an offer to co-author and direct the next Rodgers and Hammerstein show. "The King and I" - "a decision I will regrets for the rest of my life."

"South Pacific" finally closed in 1954, after 1925 performances - at the time the sixth-longest run in Broadway history. It was soon evident, though, that it would continue to be seen and heard long after it ceased to be tropical. For as Brooks Atkinson wrote in his book "Broadway," 25 years after his experiences on the day of "South Pacific's" opening this musical drama "expressed the real genius of Rodgers and Hammerstein - their insight into character and their sympathy for the common dilemmas of people. More than any other pair they mastered the technique of the modern musical theater. But they also believed in human beings."

On the day after the closing, The Washington Post editorialized, "It is disillusion to learn that the play is mortal after all." In retrospect, we need not have worried.