She's an exuberant young lady with a fondness for all things fancy—and a book character whom readers certainly fancy. Fancy Nancy, written by Jane O'Connor and illustrated by Robin Preiss Glasser (HarperCollins), has proved a smash hit, with 400,000 copies in print since December 2005. Now Nancy returns to strut her stuff in Fancy Nancy and the Posh Puppy, due from Harper in March with a 250,000-copy first printing. And this tiara-loving heroine may soon be moving beyond the page; this week the publisher finalized a deal with United Media for licensing rights to the Fancy Nancy character.

O'Connor, who is v-p and editor-at-large for Penguin Books for Young Readers, did not have to search far for her inspiration for this glam gal. "I think as an adult I am quite understated—which is a fancy word for plain," she says wryly. "But as a child, whenever my grandma and other relatives would arrive for a Sunday visit, I was all ready for them in my tutu and cape, galumphing around the house. And I think that is in every little girl. Sometimes as a kid it's hard to get noticed, and for little girls it's fun to dress up in things that glitter. There is definitely a part of me in Nancy."

The author, who has penned more than 30 books for children and whose first adult novel, Dangerous Admissions, will be published by Avon in August, says that the idea for Fancy Nancy struck her quite suddenly, one summer night in 2002. "It was after dinner one evening that the title just came to me," she recalls. "I sat down and wrote the first and last paragraphs. The rest of the story took me awhile, but the beginning and the end just flew into my head."

Glasser on tour for Fancy Nancy.

Fancy Nancy had no trouble finding a home. Margaret Anastas, editorial director-at-large for HarperCollins Children's Books, who used to work with O'Connor at Penguin, was immediately intrigued by the character when she first heard about her. "One day, while having lunch with Jane, I asked if she was writing anything at the time," Anastas says. "She told me she was working on a manuscript about a slightly ridiculous little girl who loves her tiaras and sparkly shoes and has a larger-than-life personality. I said I'd love to see it and she sent it to me. I think I began editing it the next day."

HarperCollins initially signed a two-book contract with O'Connor, who has subsequently signed to write 13 additional Fancy Nancy titles across a variety of formats, including three more picture books, beginning readers, 8x8s and sticker books.

The more time she spent with the book, Anastas says, "the more passionate I became about it. There was something so right-on from the start that I felt if this book didn't work I should find another job. From the beginning this was a book that knew its audience very well, and we were able to take advantage of that in terms of packaging, marketing and publicity."

One of the editor's first steps was getting Robin Preiss Glasser on board to illustrate Fancy Nancy. "I thought from the very beginning that Robin would be the perfect illustrator for this book, and two other people in-house happened to propose her for the project within the week," she recalls. When she saw the manuscript, Glasser also took a fancy to Nancy, yet given her busy schedule she could not complete the art for several years.

Anastas observes that it was an ideal author-artist pairing, since "Jane and Robin from the very beginning had a clear vision of who Nancy was in terms of her looks and personality, and their visions were very similar. Together they created a character who turned out to be magical."

And, as it turned out, one who begs imitation. O'Connor and Glasser discovered, as they embarked on a national tour last spring to promote their book, that there are plenty of Fancy Nancy wannabes out there—from Los Angeles to New York. They were greeted throughout their tour by girls dressed in their fancy best. "At every store there were at least two little girls I wanted to take home," says O'Connor, who remembers with special fondness one young fan who arrived wearing blue jeans, a tutu, glittery shoes, a tiara and a Lone Ranger mask, which she didn't take off the entire time. "She was to me the most like Fancy Nancy—just a little off-kilter," the author says with a laugh.

Glasser and O'Connor also played roles during bookstore appearances, the former arriving fancy and the latter plain. "I had a bag of accessories so that the kids could dress me up," says O'Connor. "They would tell me I wasn't nearly fancy enough and drape me with boas. Then we gave them cookies with holes in the center and instructed them to wear the cookies on their pinkies like rings and to nibble them daintily while turning to each other and saying, 'This is delicious, isn't it, darling?' They loved it!"

Author and illustrator will again have the chance to present fancy lessons in late March, when they hit the high road to promote Fancy Nancy and the Posh Puppy on an eight-city tour (a TV satellite tour is also planned). For this sequel—in which Nancy finally selects the perfectly posh pooch for a pet—the publisher has created an event kit to help retailers host a fittingly fancy fête. The kit includes invitations, name tags, sparkly stickers and paper dolls. Also available are floor displays featuring a Fancy Nancy standee. And [HarperCollins's Web site] will offer activities to download.

All of which points to a decidedly auspicious—that's a fancy word for promising—launch to Fancy Nancy's second act.