When Dizzy Gillespie's cheeks puff out, the world's blowfish hang their heads in shame.

It's a truly magnificent, mind-blowing spectacle: The bent-bell trumpet goes to the mouth, as it has so many thousands of times over the last 50 years on such signature tunes as "A Night in Tunisia" or "Manteca"; the neck and cheeks pop out balloonlike, as if hydraulically inflated. It's just Gillespie's unorthodox way of storing air and building up pressure for the aggressive ornamentations, complex harmonic alterations and rhythmic explorations at the heart of his beloved be-bop, but like his perpetually quizzical demeanor, it's the distinctive visual trademark of a man who's made an indelible aural mark as well.

"It's possible {people} might know me and not know my music," he says. "But once I let my jaws go, the world knows."

Unlike Gillespie's trumpet sound, no one has ever managed to copy the cheeks -- a fact for which he's thankful. "It is the wrong way to play," he says, laughing. "People figure that out quickly enough." He didn't even develop the technique, he adds. The cheeks "just started doing it, coming out." Like Dizzy Gillespie himself.

With his 70th birthday on the October horizon, and a half century of performing around the world (to be marked tomorrow night with a tribute at Wolf Trap) Gillespie might be excused for slowing down just a bit. Yet when he walks on stage to perform, he projects the gracious energy and giddy enthusiasm of youngsters mere fractions of his age.

"I really don't know where it comes from," he says in his characteristically warm, raspy rumble. "But I shouldn't be this active at this age."

He says this without true conviction. Gillespie is, after all, just about the last of the be-bop giants who stood the jazz world on its ear in the mid-'40s, and he seems to thrive despite the incredible demands made on him by incessant travel and the rigors of his particular discipline. It's a lot to ask of a young man, much less a mature one.

"Yeah, it is, isn't it?" he muses. "But I never think about it. I just get up and do what I have to do, you know.

"One advantage I have is that I am a super procrastinator. It would make it more difficult if I did things when they were supposed to be done -- wake up in the day with a sheet in my hand, go down the list, do this, do that. But I don't do that, man. I wait until the last minute and then I rush.

"I do that in everything -- except music. There are no shortcuts to music. Whatever the problem is, you have to face it, and then try to top it."

Still, Gillespie scoffs at the idea that he keeps on out of a sense of mission, to spread and perpetuate the gospel of modern jazz.

"It is important to be out there, to be seen and to be heard," he says. "But it hasn't always been that way and I've always been this way. Now that I'm older I go about the same way I did when I was younger. I'm not the last of the Mohicans.

"There are still people out there who were around in the early days, like Sonny Rollins and J.J. Johnson. They're not as old as I am, but they're close."

Rollins, Johnson and three dozen other jazz greats -- including such trumpet progenies as Wynton Marsalis, Freddie Hubbard, Jon Faddis and Jimmy Owens -- will join Gillespie tomorrow night at Wolf Trap, where he will receive the Wolf Trap Medal for Excellence in the Performing Arts. Many of them will be joining Gillespie today on the American Zephyr, a restored 1940s train (but not, of course, the A train) that will carry them down from New York City.

Wolf Trap has planned an ambitious program tracing Gillespie's considerable contributions over a half century, from his legendary be-bop instigations in the company of Charlie Parker, Thelonious Monk and others to his influential modern big bands in the late '40s and his lifelong championing of Afro-Cuban and Brazilian music.

The tribute, which will be videotaped as a segment of next season's "Wolf Trap Presents" series, is just one more in a life filled with honors and honor, but there's nothing in Gillespie's demeanor that suggests he's about to start resting on his laurels.

"I can't do this forever," he concedes. "I'm acclimated to that fact, that there will come a point in my life where I'm just not able to do it. I'm physical, like everybody else ... But I don't ever expect to stop."

Nor does anyone else. "Duke {Ellington} was the same way, and Picasso did it till he was 91," says Quincy Jones, a self-described "Dizzy junkie" from his days as a Seattle teen, and later an arranger for Gillespie. "That's the way it's supposed to be. What else is he going to do?"

Anyway, the trumpeter's mission is far from complete, though even Gillespie will admit that getting attention for the music is far different than it was 45 years ago.

"It's easier now because people know who I am. That has some validity. If you step out of a car in a little town in France and you see a Frenchman look up at you like this and recognize me, it does something to you."

John Birks Gillespie was born in Cheraw, S.C., in 1917, the last of nine children of a bricklayer who was also an amateur musician and thus kept lots of instruments around the house. Gillespie actually started out at 14 on the trombone but abandoned it when he found his arms were too short to reach some positions. A year later he settled on the trumpet and, self-taught, spent the first year playing only in the key of B-flat. Obviously, he had a lot to learn, and began doing just that at the Laurinburg Institute, an industrial school for blacks where Gillespie started gobbling up harmony and theory -- and learning to play in all keys.

Gillespie's father died when he was 10, and in 1935 the family moved to Philadelphia. By this time, Dizzy (the name derived from an offbeat, irreverent and incessant sense of mischief that has shown no signs of diminishing over the years) was starting to play around town, very much in the style of his idol, Roy Eldridge, who was then working in Teddy Hill's band. In fact, Gillespie's first major break came in 1937, when he replaced Eldridge in that band.

"I was only aware of Roy Eldridge," Gillespie says of his early style. "Roy played in the style of the older guys {like Buddy Bolden, King Oliver and Louis Armstrong}. It was the warmth of his playing that all of us young trumpet players followed; I wasn't the only one. But when I heard that style that Charlie Parker was playing, that was it."

Before the Parker collaborations, however, there would be continued apprenticeships in the big bands of Cab Calloway (ended after one of Gillespie's midperformance spitballs provoked a fight with the band leader, who emerged with 10 stitches in his behind), Earl Hines and finally Billy Eckstine. It was here that Gillespie started developing a more personal style evidenced in his tone and his increasingly adventurous solos -- a process well documented on the Smithsonian's two-record "The Development of an American Artist" and well described in Gillespie's "To Be or Not to Bop," one of the great jazz memoirs.

The Eckstine band -- which included, among others, Gillespie, Parker, Dexter Gordon, Art Blakey and Sarah Vaughan -- was be-bop's prime incubator. Because of a musicians union ban at the time, it was never recorded, but it did bring Parker and Gillespie, who had been doing parallel experiments with new rhythmic and harmonic concepts, together for the first time in an extended manner. They had jammmed before, but hadn't really had a forum for the intense explorations that would be carried out over the next few years.

What came to be called be-bop -- after a characteristic rhythmic figure found in the music -- was a watershed moment in the history of jazz, one that modernized and polarized at the same time. While it excited many musicians and led them -- via new chord progressions and substitution chords based on the higher intervals of the scale -- to reconsider their basic options, it irritated many of the critics of the day. Some of them dubbed the free-flowing articulation and frenetic invention, the unbelievable, literally breathtaking runs and double- and triple-time passages, "Chinese music."

It was along New York's fabled 52nd Street, "the street that never slept," that the musical pot bubbled be-bop at clubs like the Onyx, Minton's Playhouse and the Three Deuces; it was there, by 1945, that Gillespie and Parker were leading their seminal quintet. "The style of the music was created by Charlie Parker, all of us know that," says Gillespie, who always credits Parker with establishing the identity of be-bop. "The style of our music is based on the way that he played. That was the criteria. You wanted to sound like that. I had something to do with the harmony and the rhythmic sense. Monk created the harmony and Kenny Clarke created the rhythm to go with it. We developed all of that to go with the music."

"It was like nitroglycerine, electricity," says Quincy Jones. "What they did was heat up the richness of the extra notes that went past the 7th and the 9th. Their playground was in the altitude above a C-7th; they took the top part of that and stretched it out. And they dealt in polytonality, with whole new harmonic and melodic concepts, all these original ideas. They broke all the rules, changed the whole concept of American music. And people still haven't caught up to what they were into.

"You could feel all those forces coming together," Jones adds, "people with the same kind of mind saying, 'This is an art as well as entertainment.' And that's what you could feel the strongest. They dealt with it, and lived for it, and some of them died for an art form that they believed in very strongly. It was a turning point from having to be considered an entertainer first and an artist second. They believed in the artistry first."

On the other hand, it was art as challenge, for the listener as well as the player -- serious music to be listened to rather than simply enjoyed, much less danced to, though Gillespie says he "danced all the way through the early days of be-bop."

There was not, Gillespie insists, any great desire to shake up the establishment -- "we just wanted to play music in a different way" -- or to exclude the traditional jazz audience. "That didn't really come into our minds. We weren't interested in what other people were going to do anyways; we were trying to do it for ourselves."

But there was, he admits, "the possibility of a wedge between the people who were listening to and the ones who were performing the music." Because their music was so complex, be-bop players tended to be impatient with audiences, and audiences responded by dismissing or ignoring be-bop in return. "That's why it wasn't as popular as soul music or hillbilly music or music that didn't take any imagination to tap your foot to or dance by," Gillespie says. "The good music required a little intellect."

Because of the intense and moody nature of players such as Parker and Monk, be-bop desperately needed a front man, a public relations man, as it were, and no one was better suited for the role than Gillespie. As intensely extroverted as the other two men were introverted, he melded his technical virtuosity and harmonic adventurousness with ingratiating showmanship to become the single most effective advocate for public acceptance of the new music. While many be-bop players snubbed their audience, Gillespie talked them up, clowned, scatted and performed endless pranks. He connected with them beyond the music.

"He was probably the only one," Jones laughs. "He stood out there, but that's his innate personality. He couldn't help it."

Gillespie also became be-bop's most visible figure, its personification, particularly after a Life cover story in 1948 that emphasized everything but the music. With his wispy goatee and horn-rimmed glasses, his penchant for berets, caps and fezzes, the trademark bent-bell trumpet, and a perpetually colorful persona, Gillespie was the clown prince of jazz.

But he also was, and remains today, a great repository of information and guidance, a great teacher whose first lesson is usually that "everything goes around the rhythm, everything starts with rhythm, it's the center."

"I have a little thing that I do with my hands to show people that rhythm is permanent," Gillespie says. He holds his palms up, flat and facing each other, and then brushes them back and forth, making a sound like brushes on a snare drum. "You can talk and rhythm will go right on," he points out. "All you have to do is put your accents on the rhythm that's already there."

While be-bop freed everybody -- including drummers, finally relieved of their duty as rigid timekeepers for dancers -- Gillespie is hardly an advocate of the free jazz that sprang up in the '60s, which often obscures a lack of fundamentals in a cacophony of sound. He calls it trying to build houses without an awareness of architecture.

"We have certain rules that you build on, and if you don't hear the bottom that the older guys put down for us to build on, if you don't use it, you're not playing our music. There wasn't that much difference in Louis Armstrong's era and King Oliver's. With be-bop there was a definite cleavage and change in the style of doing the music, not the notes themselves.

"That's why I don't care how the new music sounds. To me, without the music of Louis Armstrong, it wouldn't have got to where it is now; and without the music of be-bop, it wouldn't have gotten there. They're all slots on a wheel."

Not that he's worried about the future. "Good musicians? They're all over. And I definitely am a teacher. If somebody learns from you, you are a teacher. They listen, those young musicians -- trumpet players, saxophone players, piano players. Teachers are the royalty, because they mold people. I like that role. As a matter of fact, when I can no longer play, that's what I'm going to do -- teach."

Even if some of his students are famously unmusical. For instance, at a 1976 White House tribute to the Kool Jazz Festival, Gillespie gently goaded Jimmy Carter into a spontaneous vocal chorus of "Salt Peanuts." It was a historic moment for the presidency, but not for jazz. Of course, had Gillespie won when he ran for president in 1964 (he was a write-in candidate), there would have been noticeable changes at 1600 Pennsylvania Ave., which would have become the Blues House. Gillespie's platform included subbing legalized numbers for income tax; adding a jazz curriculum in every American school; and naming Miles Davis head of the CIA (the FBI was to be disbanded), Duke Ellington minister of state and Thelonious Monk roving ambassador plenipotentiary.

Unfortunately, 1964 was Lyndon Johnson's year.

Havingfueled the be-bop pump in the early '40s, Gillespie continued to explore, refine and advance his music. His late-'40s big band, the first to project the complexity of be-bop onto a larger canvas, was extremely influential, not only on other contemporary bands, but on television and movie scoring. The Modern Jazz Quartet emerged from this band, its chamber jazz format designed to give that hard-charging unit a chance to rest. But Gillespie's big band never achieved economic stability before disbanding in 1950, though he has continued to experiment with larger ensemble projects.

"There are many ways to express yourself if you have the money for it," he sighs.

In 1947, Gillespie made another major contribution by championing the rich rhythms of Afro-Cuban and Caribbean music, hiring the fabled Cuban conga player Chano Pozo to play "Cubana Be" and "Cubana Bop" at Town Hall. It's not that such rhythms hadn't been around -- Jelly Roll Morton had incorporated "The Latin Tinge" and Gillespie had sat in with Cuban bands in New York in the '30s -- but often they were treated as nothing more than spice. Gillespie saw them as roots, "part of a rich inheritance of multirhythms. That music hasn't changed much from Africa."

In 1956, he made new discoveries when the State Department sponsored the first jazz tours of Africa, the Middle East, Asia and South America. The ambassador at large? Dizzy Gillespie, of course.

"I definitely am," he says, the mantle still comfortable. "When we first went out they didn't know a lot about our music. In Pakistan, they thought Armstrong was tires and rubber. When that happens, you're in trouble."

Of course, Gillespie and his band, which included Quincy Jones as arranger, spread the gospel. "There's nobody on the planet like him, and working in that band is one of the richest memories in my life," Jones says, adding that in terms of Afro-Cuban and Brazilian influences, Gillespie "is single-handedly the pioneer. Dizzy did a record in Brazil then with Astor Piazzola, who does a contemporary modern tango, and you knew right then it was the beginning of a whole new concept of music.

"Dizzy played his music with a samba rhythm section, and in the front row of the hotel were three teen-agers -- Antonio Carlos Jobim, Astrud and Joaåo Gilberto. As long as I live, I'll believe 'Desafinado' was influenced by that moment because it sounds like a Dizzy Gillespie solo."

Although he's long stopped touring for the State Department, Gillespie is still a student and champion of Latin music. Most Mondays, he's at New York's Village Gate, sitting in with two Latin bands, playing four sets, and trying not to get distracted. "If my mind wanders, I don't know where they are when I try to come back. You never see guys tapping their foot in Latin jazz like they do in our music."

He's convinced we're moving to a world music "based on what has been developed in the western hemisphere. It will be organized and unified one day, and not long either, 10 or 15 years. Some good music will come out of that, using European harmonies and the {rhythms} of Africa {that have} come through Brazil, Cuba, the United States and the West Indies."

In the meantime, Dizzy Gillespie plays on, enthusiasm undiminished. Wolf Trap is a celebration, but so is his everyday work. The stage won't be as crowded when he comes back to Blues Alley for three nights at the end of June, except for memories and possibilities, which is probably how Dizzy Gillespie likes it. He's never surrounded himself with young players or old players, just great players. And there's no one who has more faith in the future of be-bop and jazz.

"Anything that's worth anything is a slow process," he says. "If it comes in fast, it goes fast. But if it comes in slowly, the longer it lasts." From the '40s to the '80s, he says, "is a short time in the history of a culture. {Be-bop} will be around a long time. It's got a good foundation."

And has had for half a century in Dizzy Gillespie.