Journalist O’Donnell uncovers her German grandmother’s secret WWII history in Inge’s War (Viking, Apr.).

Your parents are German and Irish, and you were born and raised in France. How did this multinational upbringing affect your understanding of WWII?

France has had quite a tenuous relationship with its own WWII narrative. Up until the very late 1980s, the default was: “Oh, everyone was in the Resistance.” It was a revisionist history. So as someone who’s not a German Jew, or from a German group that was persecuted during the war—you carry some of that guilt with you. And when you’re taught things about WWII, you have this sense of foreboding—how do my relatives fit into this? There’s a kind of reticence. It’s not a subject you’d approach very openly, certainly not with grandparents.

Early in the book, you visit Kaliningrad, the city your grandmother fled at the end of WWII, when it was still part of Germany. How did that visit help to deepen your relationship with her?

From the moment I saw her after coming back from Kaliningrad, there was something that had changed. It’s like we had something in common that went beyond the bonds of a blood relationship. She hadn’t felt the need to share the things she’d buried for 60 years, and then, all of a sudden, she just had to tell someone. Because of our newfound closeness—that shared sense of place, where I had specifically been to the places she described—I think she chose me to tell the story to.

What misconceptions do you think you held before you started your research?

When I first thought about Hitler’s rise to power, I found it very hard to understand why you wouldn’t have risen up against it. But the Nazis’ persecution of Jews was implemented over several years. They did everything by the book; it took the form of suppression and prosecution carried out by the judiciaries, through laws. Before you know it, the abuses of power are normalized. You don’t realize you should have said something until it’s too late.

One of the book’s most rewarding qualities is the amount of complexity and ambiguity that rises to the surface.

I think telling the story through a woman’s eyes was key. Women of that time kept the household together, they fed the children, they were the ones left behind to adapt to war in the everyday. As a result, they made some very difficult choices. Unpalatable. Sometimes these decisions are not what you particularly want to hear or imagine, but they’re real.