The Lady from Zagreb” is Philip Kerr’s 10th Bernie Gunther novel, and if you’re already a fan, that should be enough to send you scurrying to your bookstore. If you’re not a fan, maybe you should take a look, because this is one of the finest series in progress. Bernie started as a Berlin cop in the 1930s, but by the time this story unfolds, in 1943, he is reluctantly working as an investigator for the Nazis; he despises them but can never quite escape them. (If he does, there’s no series.) The Nazis tolerate his stubborn independence because he’s smart and therefore useful, and also — because most of them hate each other — he’s relatively non-threatening. If he stops being useful, they can always kill him.

Besides being expertly written, the Gunther novels possess a special dimension because they don’t offer make-believe evil, but rather a fact-based portrait of the real thing — evil as bad as the world has ever known. At different times, Bernie has worked closely with the mass murderer Reinhard Heydrich (and rejoiced at his assassination) and with Hitler’s loathsome minister of propaganda, Joseph Goebbels. Some people may not want to read about these creatures, but for many they hold a sinister fascination. Beyond that, we need reminders that evil is ever with us, even though Berlin is no longer its epicenter.

In “A Man Without Breath” (2013), Goebbels sent Bernie to investigate the execution of thousands of Polish officers whose remains were found in a mass grave in the Katyn Forest. It was Goebbels’s fantasy that if he could prove that the Russians had committed this horrific war crime (they had), he might destroy the Western alliance. That didn’t happen, but in this new novel Goebbels again summons Bernie, this time for a very different assignment — one involving a woman, the lady of the title.

Goebbels, who was relatively well-read for a Nazi, controlled the German film industry. Despite being pint-sized, married and singularly unattractive (“like some malign and understandably abandoned child,” Bernie muses), he has fallen in love with a young movie star named Dalia Dresner, who the author says was suggested by Pola Negri and Hedy Lamarr. Goebbels wants her to star in a new movie, but the actress is resisting, all too aware of his designs on her (he was a notorious womanizer), and it’s Bernie’s job to persuade her.

The rumpled, 47-year-old Bernie is soon in bed with the gorgeous actress, knowing full well that he’s a dead man if Goebbels finds out. The actress tells Bernie that he’s wonderful and she seeks only to please him: “All that you’ve ever wanted from a woman is exactly what you’re going to get.”Bernie believes her, although we readers suspect that, as Sam Spade would put it, she’s playing him for a sap.

“The Lady from Zagreb” by Philip Kerr. (Putnam)

In books that contain so much horror, Kerr must from time to time offer readers some relief — romantic, comic or otherwise. Bernie’s romps with the accommodating movie star are one example, as are his bitter wisecracks about the Nazis. Beyond that, Kerr also dramatizes not only some of the war’s well-known moments — the Katyn Forest killings, the Russian front — but atrocities we may have missed. In one episode, Goebbels sends Bernie to find Dalia’s father in what remains of Yugoslavia, where Serbs and Croats are busily massacring each other. The father, an ex-priest, proves to be a monster who runs a concentration camp and proudly displays a saw “with a razor-sharp curving blade” that he boasts of having used to “cut more than thirteen hundred Serbian throats in a single day.”

Dalia flees to Switzerland, where she lives with her older, endlessly forgiving husband. Bernie follows her, only to be almost killed by American spies even as we learn about the precarious Swiss neutrality. Hitler never got around to invading, but he wanted to, and Kerr reports that the Swiss had a plan to blow up the major mountain passes into their land to stop any invasion.

Countless histories of the Third Reich exist, but there can be few more palatable ways than these novels to take a look at its horrors, its leaders and the mood in Germany before, during and after the war. The 10 books don’t relate Bernie’s story in chronological order, but it’s probably best to approach them in their order of publication. You could certainly start with this one, but after that you would do well to return to the first three — the celebrated Berlin Noir trilogy of “March Violets,” “The Pale Criminal” and “A German Requiem.” It’s an agonizing story, exceptionally well told.

Anderson regularly reviews mysteries and thrillers for Book World. For more books coverage, go to washingtonpost.com/books.