Inside the main gymnasium of Santa Rosa's Maria Carrillo High School, it sounds like a thunderstorm. Feet are pounding the bleachers as 2,400 ecstatic kids roar and cheer. No, it's not a Britney Spears concert. They're welcoming J.K. Rowling, a soft-spoken single mom from Edinburgh, Scotland, and the creator of a heroic boy wizard known as Harry Potter who has the reading world at his feet.

"I usually hate to read, but I love the Harry Potter books," said Gaby Tomko, 10, of Mill Valley. "I've been a fan since the beginning. I love all of the names of the magical creatures."

Trevor Wallace, 9, came from San Anselmo with his friends Billy, Will and Cameron to see Rowling. A grown-up friend stood in line for three hours to save them seats.

"The books are all so exciting, I can't get enough of 'em," said Trevor, dressed in a wizardly purple cape. "They're not like the usual wizard stuff with hats and stars. They're neat!"

Harry -- a skinny kid with big glasses who happens to be a wizard -- is the fictional hero of a trio of children's books -- "Harry Potter and the Sorcerer's Stone," "Harry Potter and the Chamber of Secrets" and "Harry Potter and the Prisoner of Azkaban" -- that has sold more than 8 million copies in the United States and 2.2 million in the rest of the English-speaking world. The books have been translated into 28 languages. And they have kids and adults worldwide abandoning their televisions and video games to rediscover the joys of reading.

The Scottish mother of the biggest story in publishing in a decade is 34-year-old J.K. (Joanne Kathleen) Rowling (pronounced rolling), who five years ago was an unemployed single parent on the dole. At a morning interview at her Nob Hill hotel, she admitted she's still a little dumbfounded by the sudden success and celebrity.

"I had no idea, really, until I went on this tour how popular the books had become," she said, taking a sip of coffee. "My fantasy was that one day someone in a store would see my name on a credit card and say, My God, you wrote my favorite book.' But I never expected this -- I never imagined being talked about and photographed. It's fun, I love it. But sometimes . . ." She pauses.

"When I first started getting publicity after finishing Chamber of Secrets,' I panicked. I couldn't write. The pressure scared me. But I got over it."

And how. Rowling has created a witty, wildly entertaining world that grown-ups adore as much as children do. The books' character names alone are irresistible: Severus Snape, Draco Malfoy and the Azkaban dementors; Muggles (nonwizard folk); and the game of Quidditch, a sort of aerial hockey played on broomsticks.

FOUR VOLUMES STILL TO COME

The latest in the series, "Harry Potter and the Prisoner of Azkaban," pits the heroic boy wizard and his friends, Ron Weasley and Hermione Granger (all of them students at the Hogwarts School of Witchcraft and Wizardry), against Sirius Black, the right-hand man for the series' nefarious Lord Voldemort. They win, of course. But not definitively. After all, there are still four volumes to go in the planned seven-book series.

In the fourth book, due out in July, Harry will develop his first crush.

"Careful readers of book three will already know who the girl is," Rowling said, smiling mysteriously.

Harry is also poised for big-screen magic in 2001. Warner Bros. bought the rights to the first two books for a reported "substantial seven-figure sum," but Rowling made sure she had script approval before the deal was struck.

"I'm more involved than I thought I would be," she said. "But I did want some control. I was very frightened of them taking my characters and having them do something that wasn't consistent with the books."

WROTE FIRST BOOK AT AGE 6

Rowling grew up in Chepstow, Gwent. A voracious reader (she loved Ian Fleming's James Bond series), she wrote her first complete fiction at age 6 -- a tale about a rabbit named Rabbit and a bee named Bee. As a college student, she studied in Paris before going on to work in Amnesty International's London office researching human rights abuses in French-speaking Africa.

During the next few years, she taught English in Portugal, got married and separated, and had her baby.

The idea for Harry Potter hatched during a long, dull train ride across England, she said. "It just came." She wrote the first book in an Edinburgh cafe while her infant daughter snoozed beside her. She still writes in cafes.

"Harry Potter and the Sorcerer's Stone" was published in Britain by Bloomsbury Children's Books in June 1997. Reviews and sales were phenomenally good. Scholastic Books published it in the United States soon after, and sales got phenomenally better. Released the next year, "Harry Potter and the Chamber of Secrets" enjoyed equal acclaim.

Still, not quite everyone is wild about Harry. A few parents groups in South Carolina, Minnesota and Georgia want the books banned from schools for allegedly preaching disrespect, "death, hate and evil."

The brouhaha makes Rowling weary. "To me it's about censorship," she said. "They have a right to decide what their kids read -- of course they do. But they don't have a right to decide what my kid or anyone else's child reads. As far as the books' content goes, my feeling is that they're not terribly well-versed in children's literature."

ROWLING'S BOOKS FOR ADULTS

Rowling has written two novels for adults but has no intention of publishing them. "They're rubbish," she said. But she will produce one Harry Potter book a year until the character turns 17. Where does Harry go after that? Rowling knows, but isn't telling -- yet.

She does say that she has just started reading her books to her own 6-year-old daughter, who was upstairs in the hotel room putting on pearly white nail polish. "She was badgering me to, but I wanted to wait until she was old enough to get it. I was afraid she'd be bored and ask me to read Winnie the Pooh' again. But instead she cried, More, more, more.' "

Fame and acclaim notwithstanding, that must have been a relief. "Yeah," Rowling said with a smile. "I was one happy mummy."

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READERS' Q&A WITH THE AUTHOR

To help all the Harry Potter fans who could not get into author J.K. Rowling's Bay Area appearances, The Chronicle offered to be a stand-in for our readers. Here are five questions from readers and Rowling's responses:

Q: Could you write a book where Harry has a twin sister Harrietta? Will you write a book where a girl is the main character? -- Jessica, age 12

A: I had been writing about Harry for six months before I stopped and asked myself why I was writing about Harry and not Harriet. And by then it was too late. He felt like a boy to me, I liked him as a boy, and I didn't want to have to put him in a dress and girl him up. Hermione is a very, very strong character. She's a caricature of me when I was younger.

Q: How did you come up with the characters' names? -- Claire Christian, age 9

A: I have a mild obsession with names. I collect good names, and I invent a lot. Quidditch is a made-up name; most of them are. I have notebooks full of this stuff, just obsolete words and words in other languages that I like.

Q: What are the 12 uses for dragon's blood? -- Kelsey Biggar, age 9

A: I have a very good reason for not telling you -- the movie script writer wants me to give him that information for the film. But I can say that the 12th use is oven cleaner.

Q: Why does Harry have to go back to the Dursleys every summer? Why can't he just go and spend the summer holidays with the Weasleys? -- Dan Zoloth Dorfman and family

A: You'll find out in book five.

Q: Is it true that the English version of Harry Potter was changed into an American version for Americans? -- Kristin Fleming and Kate Barber

A: There are only tiny differences, just wherever I used words that, in American English, would mean something different. The classic one was having Harry and Ron wearing "jumpers." In America, that's a dress for a small child. In Britain, it's interchangeable with "sweater." So we just changed it to sweater throughout, rather than having kids think Harry and Ron were in drag, which I didn't feel was appropriate.

-- Neva Chonin

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WHERE TO MEET J.K. ROWLING

"Harry Potter" author J.K. Rowling will appear at 11 a.m. today at Cover to Cover, 3812 24th St., San Francisco, (415) 282-8050.