"Genius? I'm not even a proper writer!"

Philip Oltermann The Observer

The story of Hans Keilson should be made essential reading for novelists who spend too much time worrying about advances, reviews and Booker shortlists. After he'd managed to get his first manuscript accepted by Fischer, a prestigious German publishing house, just before his 23rd birthday, it was promptly pulped a year later. That was 1934: Keilson's Das Leben Geht Weiter ("Life Goes On") was his publisher's last novel by a Jewish author before the Nuremberg race laws came into effect.

   After the war, he enjoyed a brief revival. In 1962 his second novel, The Death of the Adversary, was a bestseller in the US; Time nominated it as one of its top 10 books of the year. The other authors on that list – Borges, Faulkner, Nabokov and Roth among them – later piled on Nobel Prizes and Pulitzers, but Keilson sank into obscurity once more.

Obscurity, that is, until 2007, when translator Damion Searls chanced on a copy of his third book, Komödie in Moll, in a bargain bin outside a bookshop in Austria, and embarked on a campaign to get it back into print. This year, just 77 years after his debut, Keilson is finally breaking into the international market. His works are currently being translated into nine languages, and Searls's translation of Comedy in a Minor Key, written in 1947, is about to come out in Britain for the first time. In August, the book was reviewed by novelist Francine Prose in the New York Times, who concluded at the end of her first paragraph ("for busy, harried and distractible readers who have the time and energy only to skim the opening paragraph of a review") that the book was a masterpiece and its author "a genius". Keilson will be 101 years old next month. Life goes on, indeed.

When we meet, on an extremely windy November morning in his house in a village outside Amsterdam, he's animated, quick-witted, and just a little cagey about his renaissance. "I thought that review was a bit extreme, don't you think? When I first read it, I thought: 'Is that really me?'" So does he think he's a genius or not? "I'm not even a proper writer!" he shoots back. Then, after a moment's pause: "Slowly, perhaps, there's a change happening inside me. Maybe I did manage to produce something which goes beyond the everyday. It's not unusual for works of literature to be rediscovered decades after they were written. But the odd thing with my situation is that I am still alive while that's happening."

Born a German Jew near the Polish border in 1909, the son of a textile merchant who had been awarded the Iron Cross in the First World War, Keilson has a biography that is also a history of Europe's catastrophic start to the 20th century. His memory of the years between the wars is vivid, though there are gaps and the occasional mix-up: "The backpack is full," he explains, which sounds like a bad translation of a Dutch proverb but turns out to be original Keilson, meaning that you can't add any new impression without chucking out an old one. He has a crystal-clear picture of his first brush with the nationalism that was about to grip the country. At school he read out a poem by the satirical Jewish poet Heinrich Heine (first line: "When I think of Germany at night/thoughts of sleep are put to flight"). Convinced that a Jew ought not to feel so ambivalent about the Fatherland, one of his classmates stood up and said: "The body of students rejects discussion of his poem. It fouls its own nest."

In 1935 he showed his first wife, a trained graphologist, Hitler's signature. "That man is going to set the world on fire," she said. Both she and his publisher were urging him to leave Germany, but Keilson tried to muddle through for a while. Having trained as a doctor but now unable to practise, he worked as a sports teacher and a swimming instructor – ironically one of the reasons why he has managed to outlive many of his tormentors of the time. Even today, he does basic exercises on his walking frame, though he regrets that he might struggle to finish the Berlin to Potsdam relay run in which he used to compete in his prime.

In 1936 he and his wife fled to Holland, where Keilson got himself a fake passport and lived in hiding a few doors down from his wife, who gave birth to a daughter from an invisible father in 1941. Comedy in a Minor Key is dedicated to Leo and Suus Rientsma, the couple who sheltered Keilson, and the experiences it describes are partly autobiographical. Wim and Marie, a normal Dutch couple in their 20s, have taken in a Jewish former perfume salesman, who lives in a secret room in their attic. One day, the man falls ill with pneumonia and dies.

If the storyline sounds familiar – Comedy in a Minor Key was first published in 1947, the same year as Anne Frank's Diary – the tone is not. Keilson is less interested in the grand historical sweep of events – crucially, the refugee doesn't end up in Auschwitz – and more concerned with quiet, everyday moments: blacking out windows, and the social awkwardness of this enforced intimacy.

It's funnier than we think a book on this subject ought to be, and brilliantly captures the black humour of Wim and Marie's situation: how do you get rid of the corpse of a person who isn't supposed to exist? When Marie tells her sister-in-law about the man in their attic, it's a classic case of keeping up with the Joneses. "One? I'd take two or four! Just not three together, that's bad in arguments and so on. It's always two against one. By the way, you don't have anyone else waiting in the wings, do you? I need to take in another three soon."

When the book is sad, it's never so in a manipulative way. At one point Wim and Marie have to go into hiding themselves, in what seems to be an old people's home. The question they might ask themselves is: are they going to stay here until they turn as grey and withered as their co-inhabitants? In many ways Comedy in a Minor Key isn't a book about the horrors of the Second World War, but a book about the very precise fear of seeing your youth drastically curtailed.

It's also a really good read: a tightly structured book with sharp plot twists. The only thing that slightly confused me while reading it was how nice everyone was. Neighbours, relatives, postmen: everyone seems to be fighting on the right side, against the Nazis. I caught myself secretly hoping for the arrival of the jackbooted villain. "But that's Holland for you," Keilson says. "Of course there were Nazis in my village, two whole families of them on my street alone. But I had a lot of friends who helped me. And I knew that I could rely on them."

What was it about the cultural climate in Holland exactly that produced such a different sort of person to Germany at that point in history? "The Dutch are self-critical. They have the critical instincts of a good tradesman. They ask themselves: how much is that going to cost me? The Germans were different then. It's incredible to think that they gave enough power to a petit bourgeois that he could start a world war without asking themselves what would happen if the whole plan went awry."

After Keilson had been in hiding for a month, his hosts asked him to join the Vrije Groepen Amsterdam, a resistance movement operating from the city's university. They equipped Keilson with an even better fake ID – checked over by the Amsterdam police – and he spent the rest of the war travelling around Holland by train, helping to arrange housing for refugee children, and using his medical training to help them deal with the shock of leaving their families. After the war he remained in the Netherlands, requalified as a doctor and became a psychoanalyst. He later used his wartime experiences in his dissertation Sequential Traumatisation of Children, the first systematic study of young people who suffered persecution by the Nazis.

I express my disappointment that the touchy-feely Dutch resistance movement sounds less glamorous than their trigger-happy French equivalent. "I could never handle guns, so armed struggle was out of the question for me. But what we did was its own type of anti-Nazi propaganda – because in Holland you simply don't deal with children in the way the Nazis did. Goebbels killed his own children – I never heard of anything like that happening in the Netherlands."

Tragically, the trauma of parental loss eventually became a much more personal subject. His relief at the end of the war was overshadowed by the death of his parents, whom he had persuaded to join him in Holland in 1939. They had refused to go into hiding and were eventually caught and transported to Westerbork concentration camp. "I was convinced they would let them stay there because of my father's Iron Cross." Only after the end of the war did he find out that they had both died in Auschwitz.

Keilson's feelings about his part in their fate are difficult to pin down. Talking to him, you sense that his responsibility still troubles and pains him, but also that he has accepted it as something that is going to be part of his life until the end. "You can't delete that sadness," he says. "And I won't delete it." He explains further by pointing me to the title of his novella. "Music is always written in a major and a minor key: they need each other to make the right sound. It's the same with sadness and happiness. The Germans produced such great music, but they didn't get their head around that bit. I am not going to blame Angela Merkel for that, though. Hatred might have been a natural reaction to my parents' death, but I have learnt that hatred only leads to self-destruction."

In The Death of the Adversary, the more philosophical of Keilson's novels, an anecdote relayed to the narrator reiterates that point. The tsar of Russia has given his nephew, the German kaiser, a herd of majestic elks as a present. The kaiser fences off a large area of woodland for the animals, but after only a short time one elk after the other is found dead, without any apparent signs of an attack. A vet is called to investigate. Reporting back to his royal leader, he confirms that the climate is perfect for the animals, the grass fresh and the water in the area unspoiled. "So why are they dying?" the kaiser asks. "Because they are missing one thing," the vet replies, "the wolves." It's easy to see why Keilson struggled to find a publisher for the book in Germany or Israel in the 1960s: the Holocaust survivor who could "see the other side of the story" doesn't really fit the narrative.

As Keilson's second wife Marita Keilson-Lauritz, a retired literary historian, comes in to collect our coffee cups, I can't deny I am feeling a little unsettled by this utterly level-headed centenarian. You expect doctors to be analytical and selfless, but when it comes from someone in  such a notoriously narcissistic profession as novel writing, it catches you unawares. "Does he never lose his patience?" I ask Marita a few days later on the phone. "Does he never get angry with the weather, or your noisy neighbours, or the zip on his jacket?"

"Of course he does," she laughs. "He's no saint. It's precisely because he knows that that he finds it easier to understand other people's flaws and excesses."

When I get up to say goodbye, I spot a chunky trophy on a side table. Marita helpfully explains that it is the German newspaper Die Welt's annual literary prize, which Keilson won in 2008, a year before Philip Roth, two before Claude Lanzmann. "Did I really win that thing?" Keilson mumbles behind our backs. His wife rolls her eyes, and for a second I worry his memory has let him down, until I detect an impish smile on their lips. I remember the young twentysomething couple in Comedy in a Minor Key and wonder if Hans Keilson is really turning 101 this year or whether he's just finally enjoying the youth and success that was denied to him in the 1930s. Guardian