British conductor Christopher Hogwood, who last night began his second week of conducting the National Symphony to near-capacity crowds, is a Cambridge classicist who has taken the arcane musical world of authentic 18th-century performance and made it the foundation for superstardom.

Right now, he's selling more records than Pavarotti. He's become ubiquitous on the international conducting circuit. And he's changed the way thousands hear Mozart and he is moving ever more deeply into the less clearly charted world of Handel. For Hogwood, 43, it's been a quantum leap from the level of low-profile, scholarly apostle to musical celebrityhood.

"I think that -- A -- you don't decide these things. And -- B -- you don't notice them," Hogwood says in his measured Oxbridge tones. "I think outside observers, finally, put, you know, the Blue period, the Cubist period and so on, on the artist. The artist doesn't see this happening. I'm not consciously seeking anything at all. It just happens to me. I have no master plan. I am surprised when new things turn up."

The vehicle for his unique public position, he agrees, is recordings, specifically the dozens he has made with his celebrated London-based orchestra of early instruments and replicas, the Academy of Ancient Music.

The combination of Hogwood and these 40-odd players -- playing with what he calls "scratchy old [gut] strings" -- is the dominant presence on Billboard's classical charts today.

There are no fewer than five Hogwood recordings on the Classical Top 40 for the week ending April 13 (only trumpeter Wynton Marsalis comes close to that, with three). Hogwood's Mozart Requiem is No. 3. There are also Hogwood's Bach "Brandenburg" Concertos, his Vivaldi "Four Seasons," his Mozart "Exsultate, Jubilate" (with soprano Emma Kirkby) and a record of Mozart serenades.

His "Four Seasons" record did even better in England, where it landed unprecedentedly on the pop charts for several weeks. It was triggered by Hogwood's appearance on a TV mega-event.

"That was because the record got an award on an English version of the Emmys," Hogwood recalls with the droll fluency of a Cambridge lecturer, which he is.

"It was the fact that I had appeared on television clutching this effigy, and saying to this enormous audience that Vivaldi would be very glad and so on. The awards were 90 percent pop, so I shared the stage with Wham! and Police and Prince and all those curious people with their bodyguards. And after me Prince came on and said, 'Hello, folks.' And people connected the sort of ethos of the two.

"In that context suddenly a lot of people heard of this music who never had before. They felt that because they went out and bought Prince's record they ought to go out and buy this curious man called Vivaldi. And, you see, within hours almost, this record, which had been selling a comfortable, sort of, 200 a week suddenly was selling 500 a day.

"It lasted about three weeks. And we were well up in the charts of the pop world, and now it's lapsed. I don't know how many they sold in the end."

Leaning back his long, slender frame on a large sofa in a Kennedy Center dressing room after a concert, Hogwood notes, "It was rather amusing to me that it was not at all the result of how we played 'The Four Seasons.' I hope they weren't disappointed, that's the only thing.

"I dread the feeling that they sold so many thousand records and people ended up saying, 'This is all a con.' That they felt, 'We don't know what this is all about.' I mean, they could feel entirely tricked. Right? I hope not.

"I think there is something infectious in 'The Four Seasons,' whoever plays it. And it may come over."

Hogwood's commanding personality flies in the face of the stereotype of the musicologist as the dusty bibliophile. Hogwood is not only a superb musician; he is a committed salesman for musical authenticity. His debut concert last week with the NSO began with a witty address delivered with lots of body English in the arms and legs a la Jonathan Miller.

"I suppose I should justify this program a little," Hogwood declared to the audience. He traced his unconventional placing of the first three movements of Mozart's "Haffner" Symphony at the beginning of the concert -- but its finale at the concert's end -- to a program in Vienna where the composer had done the same.

"Music is a public art," Hogwood says backstage. "I like teaching. I don't like people being in the dark as to what's going on. I don't know why there should be a moat between the performer and the audience. I don't really see why we should dress up in white tie and tails. I find that to adapt Edwardian or Victorian dress to play 18th-century music to a 20th-century audience is fairly absurd. The clothes don't affect the sounds you make."

Hogwood's increasingly frequent appearances with the major American orchestras rule out the use of early instruments -- with their gut strings, shorter bows and lower tuning -- that are at the core of the Academy of Ancient Music's performances. But there are other essentials to pass on to players on modern instruments.

"You begin to establish ground rules of expressive quality," Hogwood says. "Very simple syntactic rules. How you paragraph. How you accent. How you don't accent. How you reflect the markings that are on the page. Mozart marked his music very well. The biggest problem is that people do not play what they see in front of them."

Hogwood and the Academy started out in the early 1970s as a recording orchestra -- making their debut with a disc of eight overtures by the fairly obscure 18th-century Englishman Thomas Arne. It was with a complete set of all the Mozart symphonies that their recordings burst out to the wide audience -- one of the volumes hitting the top of Billboard's classical chart.

Because it was new, says Hogwood, "we ran the risk that listeners would say this is complete tripe and is an invasion of a lot of lunatics into what is a perfectly respectable classical repertoire . . . But instead the listeners decided that the scratchy old strings deliver a certain clarity and speed . . . which we haven't heard before."

Hogwood's performing career has virtually ruled out his work as a musicologist, which once consumed 50 percent of his time. Nonetheless, Hogwood found time to write "Handel," an analytical work published this year.

While welcoming the increased interest in Handel's music, he does not always approve of the forms it takes. Of the Metropolitan Opera's centennial-year "Rinaldo," its first Handel opera, he remarks scathingly, "To tell the truth, they didn't really do 'Rinaldo.' They did part of 'Rinaldo,' laced with a few pieces that were not 'Rinaldo' at all, and leaving quite a bit of 'Rinaldo' in the trash can."

Reminded that at least the music got heard, Hogwood rejoins, "Well, I'm sufficiently a Jesuit to believe that you get people in for the right end through the wrong means."