Benny Goodman is sliding gracefully into his 74th year, a spectacled king whose swing is as carefully monitored as his words are carefully chosen.

Goodman will celebrate his 73rd birthday today with an evening concert at the Kennedy Center, the opening salvo preceding Sunday's all-day Kool Jazz blitz which brings several dozen major jazz figures together for Washington's biggest jazz event in decades.

Since his reputation was secured more than 40 years ago, when his fluid, free and graceful style rode above hard-charging big bands, Goodman has little to prove, but he seems to be enjoying his senior statesman status. Earlier in the week he stopped off in Baltimore to receive the prestigious Peabody Medal from the Peabody Conservatory, recognizing his contributions to classical music as well as jazz.

He was certainly a right man in a right place at a right time: '30s America was reeling under the double-whammy of the Depression and Prohibition. But with Goodman and his big band setting down an enthusiastic rhythm amd a happy, joyous sound, Americans came out swinging.

"I guess those days were romantic, weren't they?" he asks, already knowing the answer. "The music is good, when you go back and listen to it, to the good records. There was a real quality--Dorsey, Berrigan, Ellington, Armstrong. It wasn't just somebody dreaming." Goodman sometimes listens to old tapes--"I hear things that I've forgotten over the years and they will sound . . . very good."

By now, the Goodman success story is old news (his autobiography, "The Kingdom of Swing," came out in 1939; Steve Allen portrayed him in a 1956 film biography). Serialized, it would include years of struggle capped by the sudden mania of swing that found fans lining up at dawn to get into the dance halls; the first professional breaking of the color line that had seperated black and white musicians; the advent of small, chamber-jazz combos even as big bands became obsolete; triumphant international tours, including the first musical breaching of the Iron Curtain in 1962.

Indeed, it's such old news that when Goodman starred in an American Express commercial several years ago ("Hello, do you know me?"), a great many television viewers would probably have answered "No." The '30s and '40s were Goodman'sglory days and though he's kept working, it's been at his own pace. "They're talking about a China tour now," he says with a genial Midwestern gruffness. "But it doesn't mean a goddamn thing to go to China anymore. Everybody goes to China."

China's a long way from Goodman's birthplace, Chicago, just as the Kennedy Center is a long way from the synagogue where he first borrowed a clarinet to play in the boys' band. Goodman remembers the past without dwelling in it; it's a time he must revisit to explain not only his jazz roots but his classical roots as well. "In my early youth, I came across all these marvelous compositions for clarinet: the Mozart quintet and trio and concerto, a Brahms quintet, two sonatas, a trio, a Weber piece--all masterpieces."

Even as he studied the classical techniques and repertoire, Goodman was exposed to early jazz recordings. There were encounters at his teacher's studio, as well. When certain black musicians came by for instruction, the teacher would bridge time between lessons by having his students play duets. The 12-year-old Goodman played with Jimmy Noone and Buster Bailey, a practice that may have contributed to the breakdown of color barriers years later.

The classical emphasis decreased as Goodman became more involved in the jazz idiom. At 14 he was on the road, playing in knee pants, trying to keep up with his studies. Like most musicians of the day, Goodman struggled for years before the breaks started going his way in 1934. He finally put his own band together for a weekly New York-based radio broadcast called "Let's Dance." As the last segement of a three-hour show, Goodman's slot tended to be hot and swinging (though the term was not yet common).

The advantages and disadvatanges of playing a new style became apparent immediately. In its first job after the radio shows, the Goodman band got two weeks' notice on opening night because the few customers at the Roosevelt Hotel complained that they were "too loud." A hastily arranged cross-country tour seemed headed for oblivion rather than Los Angeles; in Denver, nightclubbers asked for their money back and the band was forced to play waltzes wearing party hats.

In Los Angeles, the Palomar Club was the end of the line; had it been a bust, the King of Swing might not have been a Pied Piper named Goodman. "I thought the further west we went, the worse things would be," Goodman recalls with a chuckle. "But they were more of a dancing audience in California." Because of the three-hour time difference with New York, the California audience had been exposed to Goodman's "Let's Dance" segment in prime time; they were primed for him and by night's end, the joint was jumpin' and the swing era had established a foothold it wouldn't relinquish for more than a decade.

Goodman, of course, became a superstar, establishing a corollary reputation for single-mindedness and a burning passion for perfection. His band had revolving chairs; players were seldom fired, but many quit under the much-feared "Goodman Ray," described by writer George Simon as "the only well-known look of contempt produced solely by the eye without any curling of the lips." Of his hard-nose reputation, Goodman simply says, "It was true. But I wasn't any harder on them than I was on myself. See, I've always been rather hard-working, dedicated to what I'm doing. I still feel sh---y if I don't do it right. I am probably a little more philosophical about it now. I can understand where it might be just plain tiredness; but in the early days, there was no excuse for being tired."

Goodman, who is far more grandfatherly than fearsome these days, points out that he was equally well-known for his absent-mindedness. "They're the same thing," he insists. "What the hell was that story?" That famous story involves his hailing a taxi, getting in while looking at new charts; after a few minutes the driver turned around to ask for instructions and Goodman blurted out "How much do I owe you?" "Oh well, that's true," he shrugs now..

Despite his successes in the world of pop and jazz, Goodman never forgot his classical roots. In 1940, he started performing as a guest soloist with various symphonies (his first concert at Carnegie Hall had been announced as "replacing Jack Barbirolli and his Philharmonic Cats, the regular band in that spot"). Once he was set to conduct the Philadelphia Orchestra when the guest soloist, pianist Jose Iturbi, refused to perform in the same concert. "The ironic thing is that he ended up in a lot of movies where he played boogie-woogie," Goodman chuckles. "That was the worst s--- in the world."

Aware of the limited repertoire for classical clarinet, Goodman commissioned concertos from Aaron Copland, Paul Hindemith, Malcolm Arnold, Morton Gould and Darius Milhaud ("too black with notes, that one"). He also commissioned a Bela Bartok concerto so complicated that his first reaction on reading it was "I need three hands." Bartok's advice? "He was cute," Goodman recalls. "He said, 'Approximate it, that's all.' "

More than 40 years after the fact, Goodman reflects on his breaking the color line by using pianist Teddy Wilson in a concert (Wilson also appears at the Kennedy Center tonight). Although black and white musicians often had jammed together and recorded together, the issue of a racially mixed band was volatile in the late '30s. Goodman's "respectability" did a lot to normalize race relations, but at the time "I didn't think it was courageous. Maybe it was, looking back. It's like being heroic in the Army. I don't think they look upon it that way, do you? You just do it; if you think about being courageous, you won't do it."

Goodman did it, sold 50 million records, put away a lot of money, raised a family, and played where and when he wanted. A good, upbeat life, for sure, and one that he seems to thoroughly enjoy; that much is written in the perpetually awry smile, the happy grin that so often finds its way onto Goodman's face.