In the summer of 1939, an ailing mother sends her teenage son to live with relatives in Denmark.

Less than a year after his arrival, Germany invades the country, which immediately surrenders and agrees to equip the Nazi forces. As the non-Jewish teen struggles to navigate life in a new place, with new friends, he becomes involved in the resistance effort to help Jews flee to Sweden.

This is the plot of “Hamlet’s Children,” a historical novel by Berkeley author Richard Kluger that will be published on Aug. 15. J. recently spoke with Kluger, who is 88 and won a Pulitzer Prize in 1997 for his history of the tobacco industry, “Ashes to Ashes.” The interview has been lightly edited for clarity.

Kluger will read from and discuss the new book Aug. 15 at Mrs. Dalloway’s in Berkeley and Aug. 26 at Orinda Books.

J.: You’re best known for your works of nonfiction about American society. What inspired you to write a World War II novel?

Richard Kluger: I was a few months past my 7th birthday the day the Japanese bombed Pearl Harbor. And I still remember vividly coming home from school the next day at lunchtime and listening on the radio for the first time to President Roosevelt. He was addressing Congress in his famous “Day of Infamy” speech, asking for the declaration of war against Japan.

I followed the war news every day closely for the next four years, and I understood even as a kid that the world had become a much darker, somber place. When I turned to writing as an adult, I had always wanted to write a book about World War II. I just couldn’t figure out how to get a handle on it because it was so much more immense and terrible than any military conflict the world had ever seen.

Why did you set the book in Denmark, a small country on the periphery of the war?

Roughly 30 years ago, a friend gave me a book dealing with the German occupation of Denmark during the Second World War. I knew nothing about the subject, and I was intrigued to learn two things. One, Denmark was treated much less harshly than all the other countries the Nazis occupied. And two, Denmark was the only conquered nation that saved its Jewish population from Nazi extermination. Both those things stuck in the back of my mind.

Five years ago, when I really knuckled down on this book, I realized the only way that I could deal with World War II as a subject was on a small canvas, and the Danish experience served as a microcosm for how I might do that.

How were Jews treated in Denmark prior to the war?

During the 19th century, Denmark became a much more liberal society in terms of social justice, and tolerance and equality becoming state policy. The Jews were just like other citizens, certainly a small minority, but antisemitism was not rife at all.

Before the war, the Jewish population was under 10,000 out of maybe 4 million people. King Christian X was on hand to celebrate the centennial of the great synagogue in Copenhagen [in 1933] in a sign of friendship from the Christian majority.

How did Sweden become a safe haven for Jews?

It was neutral and not occupied by the Germans. It was the only place that they could escape to.

Niels Bohr, the Nobel Prize-winning physicist and probably the most famous Dane of his time — we see him a bit in the new “Oppenheimer” movie — escaped just before the crackdown to Sweden, and he went to see the king in person and said, “Please announce that you’re opening your shores to the Jews of Denmark.” And that’s what happened.

Why did you decide to build the novel around a non-Jewish protagonist?

The book is not so much a book about the Jewish experience during the war as it is the Danish experience and why the Jews were treated in this remarkable fashion by their Christian countrymen at a time when their danger was at its height.

What’s the meaning of the novel’s title?

There’s a famous line by Horatio in the first act of “Hamlet”: “There’s something rotten in the state of Denmark.” He was talking about the fact that Hamlet’s father had been murdered by his brother-in-law. So I jumped forward and made the leap that there was something terrible in the state of Denmark going on 500 years later, namely the Nazis and their occupation.

“Hamlet’s Children” by Richard Kluger (Scarlet Tanager Books, 472 pages)