"Tall, pointy hat," one girl says.
"Long beard," says another.
"Right!" Stroud says, quickly adding each component to his drawing.
And that, he tells them, is exactly the sort of magician he didn't want in his new book, "The Amulet of Samarkand," the first installment in what he's calling the Bartimaeus trilogy.
Some in the book world see so much promise in the series that they've deemed it "the next Harry Potter." The first book - recently released both in Stroud's native England and the United States - is already being turned into a movie by Miramax Films, sister company to the Disney affiliates that are publishing the book in this country.
Stroud, a 33-year-old author who lives just outside London, is well aware of the inevitable comparisons to J.K. Rowling's wildly popular Harry Potter series. As a former children's book editor, he knew magic was a hot topic when he began writing this book.
"The problem was wanting to do something different," he says of the idea, which came to him as he walked home from work in the rain one evening more than two years ago.
"I was trudging along, feeling very depressed about life, carrying heavy shopping bags," he tells his young audience. And then the idea - and book's main characters - came to him.
After arriving home, he sat down and almost immediately wrote the first three chapters - "It all just came out of nowhere."
The magicians in his story are, in fact, the bad guys.
"And they look something like this," Stroud tells the audience, flipping his paper pad to a new page and drawing another figure. The crowd of young people and parents who've gathered at Anderson's Bookshop in Naperville, Ill., smile and laugh.
This time, the magician is a youngish man in a business suit, carrying a brief case. His name is Simon Lovelace, and he's the book's main villain. "I suspect he has all kinds of evil traits," Stroud says with a smirk.
The protagonists are Nathaniel, a young apprentice magician who wavers between doing good and evil, and Bartimaeus, a "djinni" - or, in the Western world, a "genie." But Bartimaeus is no eager-to-please do-gooder flowing out of a bottle.
Stroud, a tall, dark-haired chap with a friendly face, had a cheeky glint in his eye when he sat down to discuss his book in an interview with The Associated Press.
"I wanted my 'djinni' to be tougher," he says of the shape-shifting Bartimaeus, who can appear as anything, from a bird or human being to a slithering puff of smoke. "He's not a virtuous goody-goody. He's a slightly more edgy portrayal of a hero."
And an unlikely hero at that. Narrating some of the story himself, Bartimaeus is a cocky, larger-than-life personality whom Nathaniel conjures up in the book's first chapter. Nathaniel orders Bartimaeus to steal an amulet necklace from Lovelace, a powerful and pompous figure who humiliated him when he was a young boy. And the adventure moves on from there.
"At the point I started writing, I didn't even know what the amulet did," Stroud says, and he's not about to tell - you'll have to read the book.
Writing children's books full-time was something he'd thought about doing since graduating from the University of York with a degree in English literature in 1992. He wrote in his spare time, publishing three children's books in England. But "The Amulet of Samarkand" was his first try at writing fantasy, and was the book he thought might give him his big break.
Shortly after dashing out the first chapters in the fall of 2001, Stroud decided to leave his editing job. He gave himself a year to "make good" while wife Gina - a book designer - supported the couple.
Stroud's agent began circulating those first few chapters. And when Jonathan Burnham, Miramax Books' editor-in-chief, read them, he immediately hopped on a plane from New York to London to take part in a bidding war for the American rights to the book and movie.
"There was something about the writing that woke me up. He's funny and quirky," Burnham says of Stroud. "The quality of the prose is really the very, very best. It's like the very best adult fiction."
Burnham believes the book will appeal both to adults and children. And that's why he was willing to offer a "substantial six figure deal" for both the book and the movie.
The first print run for the book was 100,000 - 25,000 more than "The Thief Lord," the debut novel by German author Cornelia Funke. Her book, billed by some as last year's "next Harry Potter," has sold a half million copies and had a consistently strong presence on The New York Times list of children's best sellers. This year, Funke released the first of her own trilogy, titled "Inkheart."
So - though his book is already being readied for its third print run - Stroud has some hefty competition.
Meanwhile, the screenplay for his book is already in the process of being written, with hopes of having a movie out by early 2005. Hossein Amini, who wrote the Academy Award-nominated screenplay for "The Wings of a Dove," is writing the script.
So far, "The Amulet of Samarkand" has been a hit with many reviewers.
One compared it to "Gulliver's Travels" because of its political undertones. (Some see the book as a critique of British Prime Minister Tony Blair, though Stroud said he never intended that.) Others critics say too much is being made of the Harry Potter comparisons.
"Despite a few basic similarities, 'The Amulet of Samarkand' is more than just a Harry Potter wannabe," said one reviewer from Australia's Sydney Morning Herald. "Nathaniel fills the basic Harry Potter, new-to-magic, young-orphan requirements, but ... it's the deviations that make things interesting. Hell-bent on revenge, Nathaniel is not a noble kid and, like his power-hungry adversaries, he is willing to use and abuse to get what he wants."
Megan Coley, an 11-year-old who came to Stroud's reading in Naperville, says she thinks the book might be too complicated for readers younger than her. But she says older kids will like the book "because of the characters and the setting."
"I think that Bartimaeus will be close to or as big as Harry Potter, but not bigger," says Megan who "can't wait for the second book to come out."
Stroud says the trilogy's second installment will focus more on Bartimaeus and Kitty, a girl who is neither magician nor djinni.
With his deadline fast approaching, he's been lugging his second manuscript cross-country during his book tour, trying to find a few spare moments to read and edit it.
Meanwhile, he and his wife are expecting their first child in December. So he figures he'll finish the second book "while changing nappies."
By Martha Irvine