In the face of authoritarian rule, what is a citizen to do? Some will join the oppressors, while others, such as the diarist of the Nazi era Victor Klemperer, will keep their heads down, hoping the horrors will pass (they usually do not). Some, generally a tiny minority, choose the path of civil courage and resistance, of activity that aims to sabotage the regime. Such acts may take many forms, one being to work secretly from within the new establishment of which you are a part. That was the one taken by Libertas Haas-Heye and Harro Schulze-Boysen, two Berlin intellectuals who fell in love and worked to undermine the Nazi war effort.

The story told by Norman Ohler, which is not newly discovered but not well known, is deeply engaging, enticingly written and extremely affecting. The author opens with a personal episode, which has the effect of universalizing one of the themes evoked, the consequences over time of nefarious actions taken long ago. He reveals the moment in which, at the age of 12, his grandfather disclosed his participation in elements of the Nazi period, handing over an envelope that contained a party membership book.

The Bohemians met in the summer of 1934 and married two years later. The relationship is one of equals, an arrangement that is open. At the time, Libertas is working as a publicist in the Berlin office of the MGM movie studio, and is a member of the Nazi party who would prefer to be a poet. A photograph from 1933 shows her among a group of employees in the American company’s swastika-bedecked office, a disturbing image that raises questions about the studio whose German arm will soon be free of Jews.

Harro, an idealist from a distinguished family that includes the venerable Admiral Tirpitz, publishes Gegner, an intellectual magazine, and soon comes into conflict with the Nazis and their propensity for torture and killing. The welts on his back shock his new girlfriend, and make him adopt a different approach. He decides he will ‘appear outwardly unsuspicious in order to change the system from within’.

By 1938 the situation in Germany is becoming ever nastier, and by the time of Kristallnacht, in November, the turn to active opposition has been made, and jointly. Such activities are processed through the piecemeal construction of an extensive group of fellow travelers, not in a party political sense but as an ‘enigmatic network’ of bourgeois and bohemian resisters.

The risks they take are serious, as Ohler’s prodigious archival work makes clear. The letters of Libertas and Harro, in particular to their families, offer the beating heart of the narrative, pulling the reader into a story that seems to unfold in real time, urgently reinforced by the effective use of the present tense. The material is original and fascinating, drawn from family papers and German, Russian and other collections, offering detail and color to the times and the dangers. To be required to read between the lines is to create a space in which the imagination begins to work its magic.

With the assistance of Hermann Göring, a friend of Libertas’s family, Harro obtains a position in the Reich air ministry. The young lieutenant becomes a contact point for Luftwaffe attachés from around the world, giving him access to confidential reports about military activities in various capitals. As documents cross his desk — including, in January 1941, the elements of a plan to attack the Soviet Union in what came to be known as Operation Barbarossa — he passes copies to friends and colleagues, knowing the material will make its way to the Soviets. He is 31 years old, and his parents have suspicions. ‘Please do not worry on my behalf,’ he tells them. ‘The length of a life is no measure.’

A contact is made with someone at the Soviet embassy. Harro obtains a code name, ‘Starshina’. He knows exactly what he is doing, and what the dangers are. So does Libertas, who supports him in his various efforts, including the production of a resistance pamphlet, ‘Concern for Germany’s Future is Spreading Among the People’. They are anti-Nazi, not pro-communist.

The community of resistance comes to be known to the authorities and is closely observed. A commission is established, in the Reich main security office, to hunt the Rote Kapelle, the Red Orchestra — as the Gestapo would call Soviet espionage networks in western Europe — headed by Friedrich Panzinger, who reports to Himmler. Harro and his colleagues are not careful enough, and clues emerge that allow the commission to pick off the infiltrators one by one. The net is cast ever wider as more are ensnared. Interrogations and torture produce details of acts that will be characterized as treasonable. One thing leads to another, the group is hauled in, there are sham trials, then convictions, then sentences of death, although not for everyone.

This is a remarkable story, powerfully told, of love and courage and of the balance in the relationship between a couple. Ohler writes compelling non-fiction, even if, as he confesses, what he really wants to do in life is write novels or make movies. Perhaps this remark left me wondering at times whether the line between fact and faction might have been crossed. There has been criticism of his acclaimed but controversial account of the propensity of senior Nazis to blitz their way into mass killing and other horrors assisted by high-octane narcotics.

There is, too, the occasional excess. Would that it was so simple to establish, as Ohler puts it, that ‘every single person in the giant machine of the Reich’ who gained knowledge of the move to mass killing is a participant who ‘becomes a murderer’.

And there are matters left unexplored. The writer Javier Cercas tells us that ‘it is more important to understand the butcher than the victim’. I would have liked more about the hunters. Panzinger, for example, was caught by the Soviets, spent years in their prisons, was turned, and returned as a Soviet agent to penetrate the West German intelligence service, the Gehlen organization. They in turn recruited him as a double agent to play him back against the Soviets. The Nazi hunter of Libertas and Harro became a Soviet spy and a spy for the West. He eventually committed suicide in 1959 when arrested by the West Germans for war crimes — not the executions of Harro and Libertas, but the killing of a French general and POW.

It’s a filthy world. That’s what makes the resisters so rare and so fascinating. To take such risks deserves recognition, and this highly readable book should give Libertas, Harro and their comrades the greater attention they deserve. Their story is a timely reminder of what some citizens are willing to do in the face of autocracy and oppression that once again haunts our times.

This article was originally published in The Spectator’s UK magazine. Subscribe to the US edition here.