The title character of Sara Pennypacker’s forthcoming novel, Pax, is a red fox named for the Latin word for “peace.” He takes center stage on the cover, illustrated by Caldecott Medalist Jon Klassen and just revealed by HarperCollins, gazing at the sunrise from the woods where “his boy,” Peter, reluctantly returned him to the wild in the days before his widowed father’s deployment.

“For a long time I wanted to write a book that addressed some of the really horrible things that have happened to children because of war, and I thought I could do it by using an animal as a stand-in,” said Clementine author Pennypacker. She tried out several animals in the main character role before settling on the “curious, highly intelligent, playful” fox. “It’s one of the few animals that you could raise from a kit, although there’s a very tiny window in which to do it and after that closes no one will be able to come near. I also needed an animal that could be released to the wild without it being completely unconscionable.”

Klassen, who has created cover art for Mary Rose Wood’s Incorrigible Children series and Kelly Barnhill’s The Witch’s Boy, says the choice to take on Pax was an easy one.

“You can tell when you read something that someone has put their whole heart into it,” Klassen said. “It felt like a big book and Pax is big on the cover. It’s a big, sweeping, love story. I almost felt like, ‘Who am I to put a cover on this?’ ” Klassen is also creating interior art for the novel.

Pennypacker says the seed for the story came five or six years ago during a school visit in Oklahoma when a librarian outlined the plot of Yukio Tsuchiya‘s The Faithful Elephants. Pennypacker didn’t know the book but the story of these zoo animals’ horrific deaths during World War II got her thinking. “I didn’t actually read the book itself until much later and I’m glad I didn’t but the idea of intelligent animals commenting on war stuck with me,” she said. “I thought I could write something allegorical about that.“

As she worked on the manuscript between other projects over the years, she discarded the allegory for a more naturalistic tale told, in part, from Pax’s point of view. “I so admired what she was doing structurally, toggling back and forth between the boy and the fox,” Klassen said. “I’m starting to write on my own and I realize a lot of the work is done when you settle on the structure. Also, her writing is beautiful and she made a lot of brave choices.”

In other words, Pax is no fuzzy talking-animals story. While working as a visiting writer Pennypacker read the first chapter aloud to a fifth grade class. The novel opens with Peter being forced by his soon-to-depart military father to throw one of Pax’s favorite toys into the woods, and leave before the fox can return with it. “We had been talking about how you have to insert motivation early on and I was asking them to tell me want the fox wants, which is, of course, he wants his boy back,” Pennypacker recalled. “But after I finished, the teacher took me by the shoulder and said, ‘You can’t leave them with that.’ Some of the girls were devastated. It really speaks to the incredible bond children can have with animals. That’s a big part of the story.”