The idea for Kate DiCamillo’s sixth novel, Flora & Ulysses: The Illuminated Adventures (Candlewick, Sept.), sprang from two of the most unlikely sources imaginable, unless you have an imagination like the one that keeps the Newbery Medalist awake at night.

One day at home in Minnesota, she opened the front door to a disquieting scene. “There was a squirrel on my front step and it was clearly not well, in extremis,” she recalls. Somehow, DiCamillo discerned that the tiny creature was still breathing, so being the brave soul she is, she backed up into the house to call a friend for help.

“I should start by saying that this is one of my sweetest, most gentle friends,” DiCamillo says. “But what she said to me was, ‘Do you have a shovel? And maybe an old T-shirt?’”

DiCamillo, creator of some of the most beloved fictional animals in contemporary children’s literature, couldn’t bear the thought of further injuring the squirrel, even if that meant putting the furry thing out of its misery. “I couldn’t sanction that but by the time I went back outside, he was gone,” she says. “I think he overheard our conversation.”

That squirrel will never know it, but he had already scampered onto a branch in DiCamillo’s fertile mind.

Around the same time, DiCamillo had another preoccupation. Her mother, Betty DiCamillo, had died in 2009; it fell to Kate to distribute her worldly goods. One item she hadn’t found a home for was her mother’s favorite appliance, an Electrolux tank vacuum. (“Frankly, she was obsessed with it,” DiCamillo says.) And because her mother had a cat and DiCamillo is allergic to cat hair, the vacuum cleaner never came into Kate’s house. She saw it every time she went into the garage.

“Somehow these two things, the vacuum and the squirrel, coalesced into a story I could write to honor my mother,” DiCamillo says.

The author’s new heroine, Flora, is the lonely, only child of divorced parents. She lives with her mother, a romance novelist, who criticizes Flora’s devotion to comic books, and forbids second helpings lest petite Flora become “stout.” Her father, “a sad, quiet man who had become even sadder and quieter since the divorce,” is, perhaps, “the loneliest man on the planet.”

Already a skilled observer at age 10, Flora spies a squirrel in peril in her neighbor’s yard, and resuscitates it after it has been sucked into the neighbor’s “all-terrain” vacuum. She names the squirrel Ulysses, and is rewarded for her rescue efforts by his instantaneous devotion to her. Ulysses has also been miraculously transformed by his brush with death.

DiCamillo says she was inspired to give her squirrel superpowers by a story in Musicophilia, an essay collection by Oliver Sacks, about an orthopedic surgeon who not only survived being struck in the head by lightning, but who within a few days began composing music and training to become a concert pianist – talents he had never had before being struck.

After his tussle with the vacuum, Ulysses gains extraordinary strength, learns to fly, to love, and to compose poetry on Flora’s mother’s typewriter.

“Those are the two big superpowers to me,” DiCamillo says. “Poetry and love.”

The book features comic-book style inserts by artist K.G. Campbell, which DiCamillo says was the idea of Candlewick art director Chris Paul. “She said, ‘Why don’t we have actual comics that show Ulysses every time he uses one of his super-powers?’ And I said, ‘Why don’t we then?’ It came out great.”

DiCamillo’s only regret is that she wrote a humorous book for someone who isn’t with her any more to appreciate it. “My mother and I have the same laugh. We both tip our heads back like baby birds and cackle, and I think this book would have made her laugh. I wish she was still here so I could hear that laugh again.”

Even the vacuum cleaner is now gone. That friend who Kate called to help her with the expiring squirrel? She got the Electrolux. “And whenever something comes up about it, she says, ‘You know, this is the best vacuum cleaner I’ve ever had.’ ”