Sara Pennypacker is the author of 17 books, including the bestselling chapter-book series Clementine. Her new middle-grade novel, Pax (HarperCollins/Balzer + Bray, Feb. 2016), illustrated by Caldecott Medalist Jon Klassen, is about love and loyalty between a boy and his fox during wartime. She'll be promoting it at the fall MPIBA and NEIBA conferences.

Pax is a bit of a departure for Pennypacker. While she describes the Clementine books as "humorous and based in a world that's secure," Pax is far from light. The book alternates between sections narrated by Pax, the eponymous red fox, and those narrated by the boy, Peter. He must return the animal to the wild when his father enlists in the military and goes off to war.

The common thread between Pax and Pennypacker's other books, which range from picture books to an adult novel, is the effort to address injustice. "There's always a sense of injustice for me – the things children have to endure," she says. "I have corrected that injustice through literature, and that is what satisfies me."

The inspiration for Pax came from a comment Pennypacker overheard about Yukio Tsuchiya and Ted Lewin's Faithful Elephants (HMH, 1988), which discusses the deaths of zoo animals during World War II. "The combination of sentient, intelligent animals and war was something I couldn't stop thinking about," she says.

Pennypacker feels that telling half of Pax from the fox's perspective makes the book more powerful. "I think it's the reason why the book hurts a bit," she says. "We're experiencing war from the point of view of a creature who can't understand it – which is what happens to children, too."

While Pennypacker acknowledges that American children suffer many losses from war, she describes what happens elsewhere in the world as "really horrific": "Children die; children are made to kill. Their homes are bombed, and enormous numbers of children are refugees. These are really hard things." The focus on the fox gives children some distance to process the subject matter. The author notes: "The very first page of my book only says one thing: ‘Just because it isn't happening here doesn't mean it isn't happening.' Meaning, we get so comfortable here that war is happening elsewhere, we're so distanced from it."

Using the fox also allows Pennypacker to deal with difficult subjects like those who lose limbs in war. "I'm not the kind of writer who could [write about] a child character [losing a limb], but I was able to do that to one of the foxes," she explains. "I knew that it would be heartbreaking to children, because they love animals. The way Peter loves his fox is the way any child would love his or her dog. The bonds that children can form with animals are really deep connections."

Pennypacker is looking forward to talking about Pax at the regionals. "I hate talking about myself, but if I can talk about writing or books I'm thrilled," she says. "These are booksellers, librarians, and teachers – you can't get a better audience than that. They love books and are so interested in how stories are told. I love them."

Author Sara Pennypacker will appear at MPIBA and NEIBA.