But Kafka did not simply write about fathers and sons: he turned the unhealthy relationship of his own experience into something altogether more surreal and dystopian. It is as if he had come to see the whole world through the prism of his own sense of existential chaos. In The Trial, Josef K is arrested, accused and hauled before the courts for an unknown crime, becoming a defenceless plaything for a cruel and faceless authority. In Metamorphosis, Gregor Samsa awakes to find he has turned into a grotesque oversized vermin, a transformation that not only disgusts but also inconveniences his father in particular. Both men are consumed with a nebulous, uneasy guilt – the knowledge that they are inexplicably wrong, and out of place in normal society.

Kafka’s second great muse was his on-again-off-again fiancée, Felice Bauer, with whom he had a difficult and no less dysfunctional relationship. Having met her in 1912 via his great university friend Max Brod, Kafka found her at once remarkably unattractive and yet strangely alluring. This woman, described in his diary as having an ‘empty face that wore its emptiness openly … almost broken nose … unattractive hair, strong chin’, seemed to have an incredible creative effect on him, and he fell into a period of intense and feverish writing. (‘How the story developed before me,’ he wrote of 1912’s The Judgement, a father-son story written in one night and dedicated to Felice, ‘how everything can be said.’)

Kafka and Felice became engaged in 1914, and almost immediately Kafka felt suffocated by her and especially by her family. ‘Had they sat me down in a corner bound in real chains,’ he wrote after their engagement party, ‘placed policemen in front of me, and let me look on simply like that, it could not have been worse.’ When Felice and other friends of Kafka’s learned of his apathy they staged a dramatic intervention – a trial of sorts – in which he was sat down and categorically informed that the engagement was off. It was shortly after this embarrassing incident that Kafka wrote The Trial, with its final judgement by an indistinct figure whom Josef K cannot make out: ‘Was it one person? Was it everybody?’

Downfall

Two years later Kafka and Felice were back on, and enjoying a romantic holiday; they became engaged again, and separated again. The relationship ended once and for all when Kafka became gravely ill with tuberculosis in 1917. It was a condition that would ultimately kill him, and from his forced pension in 1918 until his death aged just 40 in 1924 he spent most of his time being looked after by his sister Ottla or by sanatorium doctors.

He continued to write during his illness – indeed, he had more time than ever to do so, his output including numerous stories and a series of letters to lovers and family members. One missive, later published as Letter to His Father, was a 103-page denouncement of Hermann Kafka’s terrible parenting.