NEW YORK • After a decades-long wave of blockbuster novels about wizards, vampires and dystopias, the latest trend in children's literature is surprisingly old. Historical fiction about World War II is having a renaissance.

"We're seeing more publishing on it than we ever have before," said Mr David Levithan, vice- president and publisher of Scholastic, noting that this is a topic that across the board is popular with children of all ages.

"It's a story with unambiguous good guys and bad guys," he said.

This year, Scholastic is publishing seven middle-grade and young- adult novels set in the period, including Alan Gratz's Projekt 1065, about a boy who joined the Hitler Youth as a spy, and The Darkest Hour, Caroline Tung Richmond's novel about a teenage spy in France.

World War II has always captivated readers. Authors and publishers say the subject has the rare potential to draw men and women as well as young and old readers to a single title.

"World War II opens up the market," said Kristin Hannah, whose 2015 novel, The Nightingale, about women in the French Resistance, has sold more than two million copies.

World War II stories may hold a special appeal because this was a conflict that young people got swept up in - as refugees, resistance fighters and youth soldiers - as dire circumstances forced them to behave like adults.

Here are three novelists who are bringing World War II to life for a new generation of young readers.

MONICA HESSE

When Hesse was 11, her father gave her a copy of Hitler's Willing Executioners. Most pre-teens would have blanched at getting a more- than-600-page book about the Holocaust as a present. Hesse, who had read The Diary Of Anne Frank over and over, was riveted by it.

"My parents knew that was what I was interested in," said Hesse, 34, a feature writer for The Washington Post.

Now she is hoping to hook other young readers on World War II stories with her young-adult novel, Girl In The Blue Coat, about a teenage girl in Nazi-occupied Amsterdam who joins the underground student resistance movement.

The heroine, Hanneke, sells goods on the black market to support her family. She reluctantly agrees to help a customer find Mirjam, a Jewish girl who was hiding in a friend's pantry, then mysteriously disappeared. Hanneke's search for Mirjam forces her to confront her own apathy and ignorance about the atrocities that have been taking place around her.

Hesse got the idea for this novel during a trip to Amsterdam two years ago. As she was cycling past Anne Frank's house, she realised how little she knew about what life was like for ordinary Dutch citizens living under the Nazis.

She learnt about the Amsterdam Student Group, whose work is central to the novel's plot. The group's young members risked their lives to rescue Jewish children who were held in a theatre that had been turned into a makeshift detention centre before they were sent to concentration camps.

"They were smuggling children out in laundry baskets, in cake boxes, in hat boxes," she said.

After Little, Brown and Co published the novel this spring, Hesse heard from readers all over the world, including a Jewish man who lived in Amsterdam during the war. She is working on another young- adult novel, set in 1943.

"I love that teenagers are openhearted and curious," she said. "Not only is this the time of life when they are becoming readers, but it's also when they are becoming actors in human society and when they are struggling with what is right and wrong, what is easy and hard, and what kind of person they are going to be."

JOHN BOYNE

While he was researching his novel The Boy At The Top Of The Mountain, Boyne visited the Berghof, an idyllic chalet in the Bavarian Alps, where Hitler spent much of his time.

"It's so beautiful and peaceful," said Boyne, 45, who lives in Dublin. "So many terrible things were plotted there."

The novel, published last month in the United States by Henry Holt & Co, opens in France in 1936, when a seven-year-old orphan named Pierrot is taken in by his Jewish neighbours. He later goes to live with his German aunt, a housekeeper at the Berghof. As he grows older, he becomes enamoured of Nazi ideology and the power that he draws from wearing a Hitler Youth uniform. Hitler invites him to war-planning meetings.

Real historical episodes are sprinkled throughout the narrative: The Duke and Duchess of Windsor visit. Eva Braun celebrates her birthday. Leni Riefenstahl and Joseph Goebbels have cameos.

The story is much darker than Boyne's 2006 novel, The Boy In The Striped Pyjamas, about the unlikely friendship between a seven-year-old boy in Auschwitz and son of a Nazi officer, which sold about seven million copies worldwide and was made into a movie.

"When we think about Germany in the 1930s, we often think if we had been there, we would not have taken part in those activities, but the reality is, you probably would get swept up in it," Boyne said. "I was interested in exploring a darker story about a child who is more easily corrupted."

RUTA SEPETYS

In Sepetys' Salt To The Sea, the paths of three young refugees converge as they flee from Russian soldiers occupying East Prussia in 1945.

Their only hope of survival is to gain passage on one of the German ships ferrying people across the Baltic Sea.

The vessel they board is the Wilhelm Gustloff. The ship was torpedoed by a Soviet submarine and sank into the freezing Baltic, killing more than 9,000, including thousands of children.

The book toggles among four narrators: a 15-year-old Polish girl without papers; a fearless 21-year- old Lithuanian nurse with a dark secret; a Prussian teenager smuggling a precious work of art; and a young German soldier.

Its climactic moments include brutal scenes of babies and children drowning and a young woman being dragged off by Russian soldiers who plan to rape her.

"I don't believe at all in simplifying the story because these young readers will take me to the mat and say, 'But how did they die?'" said Sepetys, 48, who lives in Nashville. "One of the reasons I write historical fiction for teens is that young people have a tremendous sense of justice."

NEW YORK TIMES

• Paperback versions of Girl In The Blue Coat ($19.90), The Boy At The Top Of The Mountain ($17.01) and Salt To The Sea ($19.80 ) are available online at Books Kinokuniya.