"I'm astounded that other people are interested in my book," says Blue Balliett, author of Chasing Vermeer (Scholastic), an art-world mystery that has won acclaim for its sui generis mix of puzzles and codes, philosophies and enigmas. To say that other people are "interested" is understatement: 10 foreign publishers snapped up rights to Chasing Vermeer before publication, and earlier this month Warner Bros. snagged the film rights.

"It's such a personal book," Balliett continues, "so much of my own way of seeing the world. It came out of my own classroom and my own questions." The author concedes that she is to some extent like Ms. Hussey, the unorthodox teacher of the sixth-grade class attended by her novel's two main characters, Petra and Calder. Balliett taught for 10 years at the University of Chicago Lab School, where the book is set (she, however, taught third grade), and her experience has left her with abiding respect for children's imaginations and intellect.

"Kids look at things in their own way, not as tiny adults," says Balliett. "They are people who deserve space of their own, as thinkers." She brought her years of observation of her students and of her own two children (now 17 and 19) to her fictional students, Petra and Calder, whose responses to the theft of a Vermeer painting demonstrate Balliett's belief that kids "have an ability to see connections and to put the world together in so much more of an elastic and fluid way than adults." With this idea, Balliett wanted almost everything in the book to exist also in the real world—from Charles Fort's eccentric book Lo! which influences Petra (Balliett found a copy of the book 25 years ago) to the Hyde Park neighborhood.

Although it was her first work of fiction, and her first book for children, Balliett says she wasn't daunted. "The book was written out of such deep conviction that I wasn't worried about whether I knew how to write fiction or not. I had so much to say that it wrote itself in a way."

However, the process was not straightforward: Balliett spent five years on the book, at first juggling her writing with her teaching (the sale of Chasing Vermeer, in 2001, allowed her to write full-time), and she claims to have a three-foot-high pile of drafts. "The book got more complex as I went along."

She is from a family of writers (her father is the New Yorker critic Whitney Balliett; her mother, Elizabeth Platt, has written a book about day care), and she wrote two collections of oral histories in the 1980s, The Ghosts of Nantucket and Nantucket Hauntings (both from Down East). When she finished Chasing Vermeer, she contacted her agent at the Doe Coover Agency, who turned the manuscript over to Amanda Lewis, the agency's children's specialist.

Balliett was amazed when five houses wanted the manuscript. "I was given a choice," she explains, "either talking to the editors and deciding, or going to straight auction. It was such a piece of passion that I felt that the right editor was much more important."

She chose Tracy Mack, of Scholastic. "She was an art history major, and she shared my vision for the book, which is not terribly conventional," she says. Brett Helquist, of Lemony Snicket renown, was selected to illustrate.

"Brett and Tracy came up with the idea to plant a code in the illustrations, related to the code in the book," Balliett says. She loved the idea, and enthusiastically responded when Helquist asked her to compose the 12-word message in the pictures.

Today Balliett is at work on a second novel featuring Petra and Calder, due out in fall 2005. "I hadn't meant to do that," she says. "But they were still talking in my head. I wasn't done with them or they with me." She says the plot involves a Frank Lloyd Wright house and a reference in another Charles Fort book to a haunted house in Hyde Park. "Ten years in the classroom has given me a backlog. I always had more ideas than space to get them out. Now I'm having a great time."