What would you do if the downstairs neighbour stalked your partner, peering through windows and leaving graphic letters and poems? What if he accused you both of sexually abusing your young children? What if the law could offer no help unless someone was physically hurt? What if you had access to a gun?

This is the terrifying set up of German author and Der Spiegel deputy editor-in-chief Dirk Kurbjuweit’s Fear.

The first of his best-selling novels to be translated into English, what makes Fear all the more disturbing is that it draws heavily from Kurjuweit’s true, traumatic experience almost 13 years ago.

“We were harassed almost every day by this man, but he was very clever, he knew the limit, how far he could go.” Kurbjuweit told The New Daily.

“That set free a lot of thoughts in my brain. I had to ask myself, what kind of man am I? Am I always very civilised and peaceful, or can I be the barbarian, the beast, to protect my family violently?”

Thankfully Kurbjuweit’s ordeal did not end in murder, unlike his novel. It opens with protagonist Randolph Teifenthaler, an architect, visiting his father in prison after the older man shoots dead the stalker, Dieter Tiberius.

Flashbacks then reveal Randolph, wife Rebecca and kids Paula and Fay moving into their bright, spacious apartment, meeting an at-first welcoming Dieter before the nightmarish descent.

Fear was, in some ways, Kurbjuweit’s therapy, though he waited over a decade to address these horrifying events on the advice of his publisher.

Dirk Kurbjuweit waited for a long time before revisiting his family’s ordeal by writing a novel. Photo: Getty

Just like Randolph, Kurbjuweit tried desperately to protect his family while maintaining a veneer of normality. The police were regularly called to their home, either by the Kurbjuweits or their tormentor.

“But they always said, ‘We can’t help you.’” Kurbjuweit says. “I asked one of the policemen what he would do in my situation and then he touched his gun. That was the moment when we thought, ‘now we are lost,’ if even a policeman says you have to solve your problem violently?”

Though they considered abandoning their home, even setting a time limit to do so, Kurbjuweit notes a stubborn reluctance to give in to their abuser.

“He did this, not us. He’s the violator, not us.

You don’t leave immediately when you are attacked.”<br />

After eight months of hell, the Kurbjuweit family’s tormentor eventually moved out. He later died of natural causes.

In the novel, Randolph is an unreliable narrator whose innocence is ambiguous.

Perhaps the most frightening moment comes when his interior monologue relays: “When I went to the playground with Paul and Fay, I behaved like a man who did not abuse his children.”

It’s revealed that Randolph’s distrustful father stockpiled guns. As it happens, this isn’t too far removed from Kurbjuweit’s childhood either.

“The house was full of guns, but my father wasn’t a violent man. He was a hunter and a sports marksman, but in a way he was very fearful. Sometimes he had to carry a gun just to feel safe.”

Despite everything they have been through, Kurbjuweit has regained his trust in society.

“I’m a journalist, I’m very much for democracy and I trust all these institutions. I lost that in those terrible months, but in the end the state helped us,” he says.

“I know that there are some gaps, but my faith in the rule of law is now stronger than it used to be. That’s a good consequence of what we went through.”

Fear is out on January 30 from Text Publishing.