The best-loved storyteller in America, a rail-thin man now on his third or fifth or eighth incarnation, is sitting in the back of a Lincoln Town Car Executive Series, tooling around the empty August streets of the nation's capital.

Jim Dale is 69, he's a Brit and he's a sensation. Again. A phenomenon. Again. And, to the public, as invisible as this sleekly polished vehicle purring through an afternoon thunderstorm.

He's the narrator, and portrays every single voice in a 200-plus-member cast, in the audiobooks of author J.K. Rowling's "Harry Potter" series. More than 5 million copies sold. Parents and kids have snapped up 350,000 audiobooks of the sixth installment, "Harry Potter and the Half-Blood Prince," in four weeks -- at a list price of $75 for the 17-CD set. Yesterday he had six recordings in the Top 13 audiobooks on Amazon. He is to audiobooks what Secretariat was to the Belmont -- 31 lengths out front, blazing away into history, the rest of the field scarcely in the homestretch.

He is talking in the car, black-and-gray hair a shade over the collar, a trace of the rock-and-roll singer he was 40 years ago, and is good-natured about his secondary role in the Potter phenomenon.

"I don't think for a minute that me going around the country doing readings is going to possibly promote the book more than the children already are," he says. "I mean, it's the book, isn't it? Children don't come to hear Jim Dale. They come to hear Harry Potter."

Perhaps, yes. But fame -- so very different from talent -- has always flirted with him this way. He started out a comical lad in the dreary Midlands of England. Song, dance, bit of a joke, got to do it all if you're going to be onstage, luvvie.

And here he is, six decades on, invisible even on Park Avenue in Manhattan, where he lives. At NPR in Washington, his face is so little known that when a producer comes into the station's greenroom, he hesitates.

"Jim Dale?" he says, scanning the room, eyebrows raised.

Of course, Dale is only a visitor to the land of Potter.

"I record the books in 14 days, do a few readings and go back to my life," he says. And: "I wouldn't call it part of my day-to-day doings."

His day-to-day, since he pulled out of a dreariness of a burg called Rothwell in 1952, has been acting, comedy, theater.

At 22, he was a British rock star. He was the first pop artist for a manager named George Martin, who would do something with a group called the Beatles. Dale had a hit called "Be My Girl," had kids run screaming up to his car, pounding on the window. (Years later, he would find a copy of the single at a used-record bin being sold for 6 cents.)

He hosted a midday TV gig in the southern part of the country, worked as a BBC disc jockey. In 1966, he wrote the lyrics for "Georgy Girl," an international hit for the Seekers:

"Hey there, Georgy girl . . ."

Dale went into the National Theatre in 1970, performing Shakespeare. He crossed over to New York theater, lording over Broadway in 1979 and 1980 in the title role of "Barnum." He won the Tony. The New York Times review: "Is there anything Jim Dale can't do?"

He won more New York theater awards in 1995 for his role in "Travels With My Aunt," an adaptation of the Graham Greene book. Dale played both the aunt and the nephew.

And then, you know, it dawned on somebody that maybe this guy could handle an audiobook.

"Jim is an actor's actor; he becomes what the script calls for him to be," said Joel Silberman, a theater director, writer and frequent musical collaborator of Dale's. Silberman is casting Dale in "A Woman of Will," which opens off-Broadway in October, as -- what else? -- the voice of William Shakespeare.

There are now so many voices contained in a single "Harry Potter" book -- at 134, he holds the title in the Guinness Book of World Records -- that engineers at Random House have created a compact disc with audio files of each voice so Dale can remind himself when a character emerges after, say, a two-book absence.

He personifies each voice from people in his life, an aunt, a blowhard he overheard in a bar. He then mixes in the multitude of accents and dialects available to the British ear -- Scots, Welsh, Cockney, Irish, south London -- and adds his idea of how Rowling describes them. The late actor John Houseman's lordly diction was the model for Professor Dumbledore, for example, but the art form is not mimicry.

"I don't know that I could do a good Sean Connery," he says.

Instead, creating a world of magic, curses and spells at a British school for wizards and witches while actually sitting in a cramped recording booth in Manhattan is a craft borne of pitch and timbre, vocal range, trading on the real-life magic of how human beings can recognize others solely by the sound of their voices.

"Sometimes, you're able to create a very distinct voice . . . from just the pace of their speech," Dale says, eyes twinkling, his voice drifting into the cadence of south London. "Did you know. That Michael Caine. Can only speak. In three words. At one time."

And then he's out of the car, walking in the back door at Politics and Prose. The Tuesday crowd is beyond standing room only. You're lucky to wriggle your way into the international affairs section, maybe wading up as far as Latin America, where the view is of a support beam. Dale is somewhere beyond, delighting the crowd with Harry, Hermione and Draco Malfoy.

"He's just fabulous," says David Bookbinder, an attorney who has dropped in after work -- without the kids -- to hear Dale. "I listen to him in the car on the way home just to relax."

By nightfall, the show is over. A little boy has asked Dale if he could come live with him. Dale politely declines. "I think your mum would worry." And then he runs out the door, rushing for the last flight back to New York. He'd like to be back for a late dinner with his wife, Julie, a fashion designer and gallery owner.

He will not be reading "Harry Potter" in public for a long time, perhaps not until the seventh and possibly last volume comes out. Yesterday he was back in Manhattan, another actor walking down Park Avenue, one of the best-loved voices of his generation, invisible again.

Jim Dale gives prizes to three finalists in a competition for kids who imitated Dale's readings of "Harry Potter."Jim Dale, the voice of the Harry Potter audiobooks, reads to fans at Politics and Prose in Washington.