How World War II became the hottest book craze…for kids

To the middle-grade audience, Nielsen was akin to a rock star, and she is a bit of one in the publishing world too. The types of books she often writes—historical novels about bombings, spies and young resistance fighters in World War II—have become some of the hottest novels with young readers starting around age 8.

Scholastic, one of the country’s leading children’s book publishers, is asking agents for more World War II fiction, even as the rest of the kids’ fiction market stagnates. At its book fairs, the publisher sees elementary and middle-school students darting over to the WWII bookcases, nabbing titles before they sell out. Books by authors like Nielsen and Alan Gratz have hit bestseller lists.

With tales of heroism and spycraft, battle scenes and bravery, Gratz and a coterie of other writers have tapped into many of the same themes that draw kids to the Harry Potter and Percy Jackson series. Instead of dragons, wizards and gods, there are Nazis and young resistance fighters.

In Nielsen’s thriller “Rescue," 12-year-old Meg Kenyon becomes part of a dangerous mission through Nazi-occupied France. In Adam Gidwitz’s recent novel “Max in the Land of Lies," 13-year-old Max Bretzfeld returns to Nazi Germany as a British spy. And in Alan Gratz’s “Heroes," two friends live through the Japanese attack on Pearl Harbor.

“There is insatiable interest," said Aimee Friedman, an editorial director at Scholastic and editor of one of the genre’s top authors, Gratz. The publisher looks for hot new titles and genres at its school fairs, she said, and quickly saw that kids wanted more: “World War II books are at the top of the list."

There isn’t a specific category of sales data for kids books about World War II overall. But print book sales of kids’ titles focused on the Holocaust, part of the World War II canon, rose 13% since 2023, to 350,000 copies last year, according to book tracker Circana BookScan. Kids’ fiction otherwise declined 1% during that time, as they continue to struggle with reading in the wake of Covid school shutdowns.

Gratz’s “Prisoner B-3087," published in 2013, about a boy who survived a series of concentration camps, is based on the true story of survivor Jack Gruener. It wasn’t long before Gratz realized he’d hit a nerve. “I got more fan mail than from my 10 previous books put together," he said.

He would go on to write “Grenade," about an Okinawan boy caught up in the American invasion of his home island, and “Allies," inspired by real events at D-Day. His novel “Resist" is a companion to “Allies." It is on the New York Times bestseller list for children’s middle-grade hardcovers dated May 18.

On the nonfiction front, Anne Frank’s “The Diary of a Young Girl" has been read in schools for decades. Earlier popular fiction includes Lois Lowry’s 1989 novel “Number the Stars," about the Danish resistance, and Markus Zusak’s 2006 novel “The Book Thief," about a girl in Nazi Germany who steals books to save them from being burned.

“The conflicts of World War II have endured as a lens of the human condition," said Julie Strauss-Gabel, president and publisher of Dutton Children’s Books and Gidwitz’s editor.

Nielsen, 53, visits dozens of schools nationwide each year from her home in Utah. Her favorite audiences include kids skeptical that stories about events that took place more than 80 years ago could possibly be interesting.

“They can’t believe it really happened and involved somebody their own age," she said. “They are the ultimate stories about good versus evil." Nielsen, whose novels “Resistance" and “Uprising" are bestsellers, added, “There is no middle ground."

Laura Cheek, a librarian who invited Nielsen to speak in April in Washington, Okla., said getting kids interested in reading has been a challenge—but Nielsen seems to have found a way in.

“Even middle-school boys who don’t pay attention to anything were sitting there big-eyed and mouths open," she said. Nielsen had a whiteboard laying out her plans for future book ideas and encouraged those in attendance to create their own stories.

“It was a very cool experience," said Stella Cheek, an 11-year-old sixth-grader in the audience. (The two Cheeks aren’t related.)

“When I think of World War II, I first think of the Holocaust, but this broadened my understanding," she added. Cheek had earlier read “Uprising" after coming across it in her school library. “It wasn’t about a Jewish girl, but a girl living in Poland when her country was taken over. It helped me understand how World War II affected everybody, not just Jewish people."

Stella’s brother Huxley, a 14-year-old eighth-grader who also saw Nielsen speak, was already familiar with World War II historical fiction. As a seventh-grader, he’d read Gratz’s 2017 bestselling novel “Refugee," about three kids—a Jewish boy fleeing the Nazis, a Cuban girl fleeing Communism, and a Syrian boy fleeing war at home—who each make perilous journeys in search of safety.

Huxley said the stories can be disturbing, but he believes it’s important to learn about them. “Hitler was obviously terrible," he said. “We should be allowed to know what happened so that we don’t make the same mistakes."

Huxley Cheek says World War II stories can be disturbing, but he believes it’s important to learn from them.

The hardcover edition of “Refugee" spent more than 280 weeks on the New York Times’s children’s middle-grade bestseller list and today has nearly 1.6 million copies in print.

Parents sometimes worry that the subject matter is too frightening for their kids, but advocates for the books say they provide a compelling opportunity to teach history.

“I tell them that these books aren’t so dark that their kids can’t read them," said Valerie Koehler, owner of the Blue Willow Bookshop in Houston.

“For kids, it’s all about word-of-mouth," said Sharon Hearn, founder of Children’s Book World in Los Angeles. Hot titles getting talked about include the 2024 book “The Bletchley Riddle," by Ruta Sepetys and Steve Sheinkin, about two siblings caught up in the drama of World War II.

Lariat Hale, a 12-year-old sixth-grader, got tipped off to Nielsen’s “Uprising" by a friend last year.

She has since read four or five of Nielsen’s other historical titles, and attended the author’s school event last month. “I liked that some of her books are based on true stories, and that she brings her characters alive with words," Hale said.

Gratz used to make frequent school visits. These days he hosts a live, online book chat every month during the school year from his home in Portland, Ore.

He thinks young readers are drawn to his stories because they appreciate fairness and are attuned to the idea of standing up for what’s right.

Author Alan Gratz says young readers are drawn to his stories because they appreciate fairness.

“This was a war we needed to fight to stop the Nazis," Gratz said. “They were the world’s bully. Middle graders understand that."

Gratz’s latest event drew about 3,000 students from 30 states and three Canadian provinces.

He began it by admitting that, in some regards, he had been a bit of a disappointment. Born and raised in Knoxville, Tenn., Gratz, 53 years old, came from a football family, but instead of going into sports, he took up writing.

As a third-grader, he said, he wrote his own newspaper, stuffing it in nearby mailboxes. Two years later, he wrote his first book, “Real Kids Don’t Eat Spinach," an advice guide about what foods to eat (pizza and french fries) and to avoid (spinach), movies to watch (“Star Wars" and “Indiana Jones") and fashion tips (shorts and T-shirts). Today Gratz has published more than 20 books.

Gratz’s first book was an advice guide. He wrote it in fifth grade.

Scholastic is bankrolling a major advertising and marketing campaign for Gratz’s next novel, “War Games," which publishes Oct. 7. Set during the 1936 Berlin Olympics, the novel tells the story of a female gymnast who sees firsthand how the Nazis have seized power in Germany, laying the groundwork for World War II.

The author will go on a 10-city tour with major ticketed events—an opportunity typically reserved only for big stars. The publisher has ordered an initial printing of 200,000 copies, an impressive number for a middle-grade title.

“The modern world comes at kids on their phones, on their computers, on their televisions and in the form of active-shooter drills at school," Gratz said. “They have refugees as classmates. They don’t have the luxury of only thinking about school, home and the neighborhood. These books help them look at the world."

Write to Jeffrey A. Trachtenberg at Jeffrey.Trachtenberg@wsj.com