Here’s an edited transcript of our conversation. Q: The event that forms the backdrop of your novel — the sinking of the Wilhelm Gustloff, with a huge loss of life — is all but unknown.

The Wilhelm Gustloff was the most lethal shipwreck in history, but some details of the sinking remain unknown. At around 9 p.m. on January 30, 1945, Adolf Hitler was speaking to the German people.

The sinking of the liner Wilhelm Gustloff was by far the worst single naval disaster in history, claiming 9,400 lives, more than six times the toll of the Titanic. But few even know about it.

The sinking of a ship that cost more lives than ... One of these ships was the Wilhelm Gustloff, which, in January 1945, was torpedoed by the Soviets and sank, killing an estimated 9,000 people.