Cary Fagan’s latest children’s novel began with a scribbled note on a torn envelope. He envisioned a quirky tale about a man who obsessively collects water samples that have been taken from historic events or natural disasters, such as the 1998 Montreal ice storm. Once he began writing, Mr. Karp’s Last Glass came together in a rush, taking only two weeks to complete.

“I have picture books that have taken me two years to finish,” Fagan says. “And that book, I sat down and it just really flowed. It was one of those exhilarating writing experiences that you hope to have, that you kind of live for – where it feels like you’re downhill skiing or something.”

That experience must have been particularly gratifying for the very busy Fagan. The Toronto author juggles a wide variety of projects, ranging from children’s picture books and novels to adult novels and short stories. Indeed, this year alone he will release three children’s books: Mr. Karp’s Last Glass with Groundwood Books in April; a new picture book, Thing-Thing, in August; and Ten Lessons for Kaspar Snit, the third volume in a series, in September. (The latter two titles are with Tundra Books.) Up for next year is an adult novel with Cormorant Books, his first adult title since The Mermaid of Paris in 2003. And he’s also working on a collection of short stories that he hopes to release in 2009.

Fagan, 50, says moving back and forth in this way keeps his writing fresh. But he started off writing fiction for adults. He self-published his first book, Nora by the Sea, in 1988 and began fielding offers from publishers thereafter. But he always wanted to write for children as well. “Certainly having children was a huge impetus to write for kids,” says Fagan, who has two daughters, now 16 and 10. “It became very starkly clear that there’s wonderful children’s writing out there, which is just as good and just as moving as any adult fiction.” He began his own kidlit career with two picture-book riffs on adult stories – Gogol’s Coat in 1998 and The Market Wedding in 2000 – before producing his first original, Daughter of the Great Zandini, in 2001.

This year’s output will bring Fagan’s total number of children’s titles to 11. All of those have been with Tundra save Mr. Karp’s Last Glass, for which Fagan signed on with Groundwood. “I was worried about overloading them,” the author says of Tundra. “I mean, how much Fagan can one house take?” He adds that once the book was finished, it seemed like a good fit for Groundwood. “Karp is very short for a novel and Groundwood sometimes publishes books of this length and does a beautiful job with them. But it was also just a feeling that the voice, the oddness of the story, would appeal to the Groundwood people. So I sent it to them first.” (Fagan also recently signed an agent, Marie Campbell of Transatlantic Literary Agency, to represent his kids’ books.)

Whatever the publisher, Fagan hopes Karp will offer something to both children and adult readers. “The voice of Karp isn’t really that different from some of the adult fiction I’ve written,” he says. Indeed, Fagan adds that in recent years, he’s noticed the boundaries of his work blurring, with the humour of his children’s stories and the ambiguity and uncertainty of his adult fiction bleeding into each other. Working in several modes also affects his approach to storytelling. For example, Thing-Thing, the story of a rejected gift, was meant to be an adult novel, but didn’t come together until he saw its potential as a children’s story. “I think of it all as writing. I don’t really distinguish,” he says, “If I could only do one, I’d feel a tremendous loss and absence.”