To readers of children's books, the illustrations that accompany the story should help provide an entry into a magical world. In the case of illustrator Mary Grandpré, that's more literally true than with most: Her most famous drawings adorn the pages of the American editions of J.K. Rowling's phenomenally successful Harry Potter books, which are filled with images of witches, wizards, enchanted castles and flying broomsticks.

For Grandpré, who recently moved to Sarasota with her husband, Tom Casmer (the new head of the Ringling School of Art and Design's illustration department), the Potter books are not so much about magic, though, as they are about hard work, which must be accomplished in a limited time frame. The illustrator says she usually has from six weeks to two months to create the cover and the black and white "spot" illustrations that open each chapter.

"I'm a slow reader, too," she adds with a smile. So as Rowling's books keep getting longer, it becomes more of a challenge to meet those deadlines. Still, Grandpré says she's luckier than illustrators in some other countries, who don't even get to read the highly guarded manuscripts of the Potter books before they must design a cover. And she admits that Rowling gives her good stuff to work with. "J.K. Rowling is such a great writer, she envisions the characters and the settings for me, and I just have to take notes."

There's no doubt the recognition accorded Grandpré because of the Harry Potter books has opened doors for her, although she hastens to add it hasn't made her rich. (Her agreement with Scholastic Books, which publishes the books in the United States, does not include royalties, although she did renegotiate her contract after the third book hit.) But the illustrator is hardly an overnight success. She's worked for more than 20 years as a professional to fulfill the artistic dreams that began as a child growing up in Minnesota.

"I was around five when I realized that drawing was really fun," says the soft-spoken Grandpré. "My dad had an artistic side, and we used to sit down and draw together. I think I got my first oil paint set when I was about eight or nine."

But art was not an important part of her Catholic school education, although she does credit it for one major influence: Attending Mass every day, she was dazzled by the church's stained glass windows. "There was a kind of luminous quality about them, a glow," she recalls, "that sometimes comes out in my artwork, whether I mean it to or not."

But Grandpré married young and spent several years working to help her husband through school. When the couple divorced, she decided to attend the Minneapolis College of Art and Design.

"That's where I found out what illustration was really all about," she says. "I had thought it was billboards and cereal boxes. But I discovered there were so many ways to make a living as an artist. I worked really hard, sometimes doing an assignment twice just to see what I could do. But mostly I just loved making art."

After college she put together her portfolio and, as beginning artists must, started knocking on doors. "I think my first job was a pastel to illustrate a frozen smoked sausage box, to show the ice melting off," she says with a laugh. "Just what I had originally feared illustration was all about."

But in time she garnered editorial assignments for area magazines, including medical publications. ("I really learned to conceptualize there," she says, "illustrating everything from kidneys to bee stings to acne.") She also realized that what she wanted to do most of all was to illustrate children's books. And, after sending samples of her work to many New York publishers, she got the chance to illustrate her first, Chen Yu Min and the Ginger Cat, for Random House.

"It was a great, character-driven story," she recalls, "and I was really bitten by the bug." Since that first book she has gone on to illustrate such children's titles as The Vegetables Go to Bed, Batwings and the Curtain of Night, Plum, and The Purple Snerd.

She was also hired by Dreamworks to paint landscapes from an ant's point of view to serve as guides for the animators of the movie Antz. "I liked the way that got me to deal with atmosphere and perspective," she says. "It involved studying nature close up, from a very exaggerated perspective."

The call to illustrate the Potter books came, she says, "like any call. 'It's about a boy with magical powers,' David Saylor [of Scholastic] told me," she recalls. Then he sent me a huge manuscript. My schedule was packed, so I called him to tell him I didn't have time. But he talked me into it." After doing the first book, she says, "I was busy with all other kinds of projects while Harry Potter was getting his feet firmly planted in the minds of kids everywhere in the world. By the time I was working on Book 3, we knew we were dealing with something very special."

Part of coming to Sarasota, in fact, apart from Tom's new job, was her desire to take a break from the business aspects of being an in-demand illustrator to discover the pure joy of being an artist again. In the studio of their home, working beside their dogs Chopper and Charlie, she and Tom are now collaborating on their own children's book, Henry and Paul. Henry is a young boy who wants to be (naturally) an artist; Paul is his dog. The book is set to come out in spring 2005.

"I would love to do more personal work," Grandpré says, and the two have discovered a method of working together that succeeds. "But I am also contracted to do the rest of the Harry Potter books. And I'm doing a picture book by another author called Sweep Dreams. I enjoy doing picture books, and playing with techniques, maybe mixing watercolors with pastels for one look or incorporating some scratched-edge lines for another. With picture books you have more of an empty slate, a bigger playground for things to happen in the illustrations that maybe aren't mentioned in the words. When I read a story I get a picture of how it's unfolding in my mind. That's pretty easy. The hard part is making that appear on canvas."