Sarah and I met in kindergarten," answers artist Warren Linn when asked how he hooked up with author Sarah Weeks to create Happy Birthday, Frankie, which HarperCollins published under its Laura Geringer imprint.

But, as it turns out, it wasn't their kindergarten year, but that of their respective children, now fourth graders, who were in the same class at Manhattan's P.S. 87. "By that point, Sarah had quite a number of kids' books under her belt," says Linn, who makes his children's book debut with Frankie. "She roped me into coming into the classroom to do some storytelling and drawing projects with the kids. Now, I have taught art at Rhode Island School of Design in the past and I currently teach classes at Parsons School of Design and the Maryland Institute College of Art, and I am quite savvy dealing with 19- and 20-year-olds. But the thought of standing up in front of 28 kindergartners was absolutely terrifying."

Yet the 53-year-old Linn, who has created many editorial illustrations for magazines and newspapers since graduating from art school, survived the experience, which led to a lasting friendship with Weeks. He credits her with, in his words, "putting the idea in my mind that maybe I could do a children's book. I have to say, frankly--no pun intended there--that I thought it was a terrific idea, but the work I've done in the past has an irony, even a dark side, to it. If the New York Times, for example, wants a drawing to run alongside an op-ed page piece with an Armageddon theme, they are apt to ask me to do it."

On a visit to Weeks's country home with his family several years ago, Linn brought along a collage as a thank-you gift. "This gift was pivotal to the development of this book," recalls the artist. "She showed the collage to her editor, Laura Geringer, and told her that she was interested in doing a project with me. When I met Laura, she was very appreciative of my collages. She herself had done collages as a child, and she encouraged me to do this book in collage."

After Geringer gave the book idea a nod, Weeks wrote the 48 words that became the text for Frankie and faxed it to Linn, who decided, "If I could do a children's book at all, I could do this one. I see it as an act of great empathy and generosity on Sarah's part that she wrote this brief text to provide me with a venue for my art. She made a conscious effort to keep the book light on text so I could fill the pages with images."

This Linn did, first creating what he terms "master boards" of his characters, depicting them at different angles and with various expressions. He used digital laser copies of the originals to make his cut-paper collages, which he then painted over. The artist notes that the prototypes for the book's protagonists--a professor and the Frankenstein character he painstakingly pieces together by trial and error--were initially "a bit too scary, but they warmed up over time. I got tenacious about getting them right and it became quite a challenge for me. Then, on about my third visit to Laura's office, I was very excited when she said, 'You now have a children's book here.' "

Linn has another children's book project on his drawing board and hopes one day to illustrate a story by his daughter, Maria. He reflects that the creative process for his first book was "really like a dream. As an illustrator, one hopes to be able to collaborate with a good word person. In this case, I was lucky to work with two brilliant word people, yet at the same time feel an autonomy."

And, though Linn believes that creating the art for Frankie generally went quite smoothly, he remembers his then eight-year-old daughter wandering into his studio during the eight months he worked on the collages. "She'd look at my work and say, 'Are you ever going to finish this book? Didn't Sarah write the story in about 20 minutes?' To which I'd reply, 'No, it took her her whole life to write it,' which is an idea I really like."