Dohnanyi said his early childhood was in fact a happy one. His father was a swiftly rising jurist and promising legal scholar, a defender of the Weimar Republic, reviled by many Germans as a state born from supposed homefront sabotage during World War I (the notorious “stab-in-the-back” myth) and burdened by Allied hubris at Versailles. After Hitler came to power in 1933, Hans was shocked by the Nazis’ contempt for the law in its treatments of political opposition and Jews. He began to secretly chronicle Nazi abuses, anticipating, Sifton and Stern write, that his record could be valuable in legal prosecutions after the regime had been deposed. Meanwhile, he began building connections among a network of fellow resisters holding prominent posts, most notably in intelligence, the Abwehr, where he was appointed in 1939.

In front of his three children, Hans maintained a complete silence about the regime, so much so that the young Christoph wondered why his father never spoke about politics. Then there were the clandestine meetings, an early clue for the Dohnanyi children that all was not as it seemed. The family home was near a river, and Christoph saw people avoiding the street by arriving by boat under cover of darkness for private conversations with his father.

“My father tried to help people,” recalled Dohnanyi. “It was not so much a political conviction — of course he hated the Nazis — but more a human approach. He just could not see people suffering because they were Jewish, or because they are against Hitler.”

In 1941 Hans learned of the imminent deportation (and probable death) of a group of Jews that included a lawyer named Friedrich Arnold, whom he had pledged to protect before the war. Hans and his colleagues then hatched an extremely daring plan dubbed Operation 7, in which a total of 14 Jews including Arnold were sent abroad nominally as agents of the Abwehr. It worked, and the entire group escaped to Switzerland. Hans even succeeded in wiring funds to support them during the war. They survived.

Initially, it was partly these related “currency violations,” as opposed to knowledge of his involvement with any assassination plots, that first led to Hans’s imprisonment, and that of Christine as well. Christine came home one month later. Hans did not.

Sifton and Stern chronicle his month-by-month journey through a series of prisons, military hospitals, and concentration camps, as he battled illness and injury, all the while withstanding Nazi interrogation, as the regime tried to build the case against him and identify more resisters. He never broke. In the early months, he kept himself sane as he awaited trial by teaching himself to sketch, creating a self-portrait and portraits of his family.

In November 1943, his prison cell was hit by an incendiary bomb during an air raid, which he somehow survived. A few months later, in order to avoid further Gestapo interrogation and as part of a desperate bid to outlast the war, he begged Christine to poison the food she brought him in order to infect him with diphtheria. His letters from the cellar of the brutal Prinz Albrecht Street prison, written on the cut-out bottoms of paper cups, have been preserved in a book called “Last Letters of Resistance,” alongside letters from Christine to the children. They are almost unbearably poignant in their mixture of details from daily prison life, pessimism about the future, and despite it all, a kind of blind, frenzied hope.

Christine did as she was asked, and the poison plan worked. With diphtheria, Hans was transferred to a hospital in Potsdam, where the young Christoph visited him for the last time. “I was able to go there secretly,” Dohnanyi recalled, “and by stepping on my bike I could sit on the window. He was there. He had his fingers taped, so I knew they had tortured him. That was pretty hard. It was then that I started to realize how it really was. . . . But he of course never said anything.”

Not long afterward, there was what Christoph von Dohnanyi described as a “Fidelio” moment when Christine reached Hans in the hospital disguised as a nurse, but their plans to escape into hiding with the children were thwarted by two guards posted in front of the house.

In the chaotic final months of the war, the family home was on the front lines of the fighting. Dohnanyi recalled it being searched on successive days by German troops in search of Soviets, and by Soviets in search of Germans. One night a drunken Soviet soldier entered the home and demanded at gunpoint the keys to the family’s car, which had not been driven in two years. Dohnanyi managed to escape out a window.

The picture for his father had by then darkened further still, as the Gestapo discovered the trove of documents Hans had prepared early in the war, linking him to the elaborate network of resisters and multiple assassination plots. Some of the documents were shown directly to Hitler, and Hans was accused of being “the spiritual head of the conspiracy” to overthrow the regime.

In April 1945, Hans von Dohnanyi was executed at the Sachsenhausen concentration camp, and Dietrich Bonhoeffer at the Flossenbürg camp, only weeks before the final Nazi surrender.

Sifton and Stern’s chronicle is brief but deeply informed. And while Hans’s name appears in most academic studies of the resistance, this new book is clearly written with a larger audience in mind. The prose conveys a sense of historical perspective but also, just below the surface, a compassion possibly born of the authors’ own long-distance links to these men and their era. Sifton, a veteran editor, is the daughter of Bonhoeffer’s mentor, the theologian Reinhold Niebuhr; and Stern, a distinguished historian of modern Germany, was born in that country and fled Hitler’s regime with his family, who themselves knew the Bonhoeffers. Together, the authors conclude: “the Third Reich had no greater, more courageous, and more admirable enemies” than these two men.

After the war, Christine and the children were flown by American forces out of what had become the Soviet sector and into Munich. To honor their father’s example, both Dohnanyi (who wears his father’s ring) and his brother Klaus studied law intensively, with an eye toward one day assisting in the rebuilding of their country.

“In those days,” Dohnanyi recalled, “we thought even if you are maybe inclining to be an artist or go into music, the most important thing is to build your country up again.”

But Dohnanyi, who had stopped playing music during the war, now found himself composing when he should have been studying law. He realized he could also help reconstitute his country’s shattered cultural life by participating in a series of Munich concerts known as Musica Viva, which championed the very modern music so reviled by the Nazis.

The tone for both brothers in that postwar period may well have been set by a remarkable letter Christine wrote to them during her own incarceration, cautioning them: “Don’t carry any hate in your heart against the power that has done this to us. Don’t fill your souls with bitterness; that has its revenge and takes from you the most beautiful thing there is, trust. . . . Believe me, when one has experienced this, then one knows that it is after all only a really small and meager part of the human being that one can put in jail.”

Christine lived until 1966. (“She was destroyed, in a way,” said Dohnanyi.) His brother became a prominent German politician, his sister married and had a family in Wupperthal, Germany. In 2003, Hans was named a Righteous Gentile by Israel’s Holocaust memorial, Yad Vashem, for his work on Operation 7.

In 1952, Dohnanyi came to the United States to study with his grandfather, the Hungarian composer Ernst von Dohnanyi, who had been estranged from the family growing up. (When Christoph stepped off the boat in New York, he was greeted by a grateful Friedrich Arnold.) As a conductor, he spent the early decades of his career in Germany until his famously fruitful period at the helm of the Cleveland Orchestra (1984-2002). These days, in addition to the BSO, to which he’ll return in March for a survey of Beethoven Piano Concertos, Dohnanyi conducts a short list of distinguished orchestras — “I’m very happy,” he says — though he sees his situation as not without irony. “In this country, my father’s name is less known than mine,” he said. “Which is ridiculous.”

It’s hard to see that changing anytime soon, but Dohnanyi seemed deeply grateful the book has now made his father’s history available to be discovered. “The more I know, the more proud I feel, because he didn’t make any kind of compromises,” said Dohnanyi. “He just did what he thought was right.”