The tragedies that followed Roald Dahl like a shadow.

Roald Dahl is best known for his fantastically twisted children’s books – but the string of misfortunes that littered his personal life created a tale more tragic than any fiction.

The first time fate threatened the military man turned beloved children’s author, he came off remarkably well.

While flying planes for the British Royal Air Force during World War II in 1940, Dahl was shot down over Libya. Dahl survived the crash, but was seriously injured, suffering broken bones and even temporary blindness. His recovery was never quite complete – the operations that saved him also meant he had trouble walking in his later years.

Still, the crash introduced him to his successful career in writing. He was asked to write about his experience of the crash as a piece to promote Britain’s war efforts. And after the war, he wrote his famous children’s books, including James and the Giant Peach, Matilda, and Charlie and the Chocolate Factory.

From there, he would not be so lucky. Although, with each subsequent tragedy, came at least a small silver lining.

His son’s accident

In late 1960, Roald Dahl and his wife, Oscar-winning actress Patricia Neal, were spending winter in New York City with their children, Olivia, five, Chantal Sophia “Tessa”, three, and four-month-old Theo.

Their nanny, Susan, was out for a walk, pushing baby Theo in his pram. They were crossing the street when a taxi hit Theo’s pram, sending the little boy flying through the air. The impact shattered his skull.

Roald and Pat had heard the police sirens wail as they attended the accident, but neither realised it was their own son who had been injured. Eventually, they were notified and rushed to the nearby hospital to see him. There, doctors told them they didn’t think the little boy would survive.

He did. But that wasn’t the end of his suffering.

After spending weeks in intensive care and undergoing multiple surgeries, as detailed by Donald Sturrock in his biography Storyteller: The Life of Roald Dahl, Theo was released from hospital just before Christmas.

But a week later, his family noticed something was wrong - their son was blind - and rushed him back to hospital, where the fluid around his brain was drained and a tube installed to keep the fluid from his brain.

The drainage tube wasn't made well enough and blocked easily, forcing Theo's parents to keep returning to hospital for their son.

Dahl, determined to help his son, worked with toymaker Stanley Wade and doctor Kenneth Till to develop a substitute valve that wouldn't block and in May 1962, the Dahl-Wade-Till Valve was finished. In the decades since, it's been used to help almost 3000 other children.

But the author's next challenge wouldn't end with such a triumph.

His daughter's death

By November 1962, the family had moved back to England and their lives were starting to return to normal. But it was short lived.

One day their seven-year-old Olivia came home with a note saying there had been a measles outbreak at her school. There was no vaccination for the disease available then, but Dahl knew that a dose of gamma globulin could boost immunity. He managed to get his hands on some through Pat's brother, but he only provided enough for Theo, thinking it would be "good" for Olivia and Tessa to get measles.

Olivia contracted the illness and seemed to be suffering mild symptoms, but nothing serious. Then, a few days in, Pat found her daughter having a seizure. She fell unconscious.

Olivia was rushed to hospital but could not be saved.

According to Sturrock, Pat was "destroyed" while Dahl was "limp with despair", and battling guilt and a sense that he could have saved her if he'd done more.

But when a measles vaccine became available in the country just a few years later, Dahl became a fierce advocate for vaccination who made a hugely positive impact, Tom Solomon writes in his book Roald Dahl’s Marvellous Medicine.

Pat's stroke and the end of their marriage

Roald and Pat did not have the happiest of marriages, but it was never more tested than when Pat suffered a stroke that almost killed her in 1965.

She remained in a coma for weeks before eventually regaining consciousness. But she had suffered brain damage and now had trouble speaking and walking.

Dahl had been told that his wife's best chance for recovery was intense stimulation for several hours at a time.

Nadia Cohen writes in her book, The Real Roald Dahl, that the therapy sessions would often end in tears, but Dahl was determined to restore his wife to her former self.

"If left alone, she would sit and stare into space and in half an hour a great black cloud of depression would envelop her mind," he wrote in a memoir. "Unless I was prepared to have a bad-tempered desperately unhappy nitwit in the house, some very drastic action would have to be taken."

It was an exhausting routine, but it worked. Pat recovered enough to resume her acting career and continue as main carer to their now four children, Tessa, Theo, Ophelia (born 1964) and Lucy, whom Pat had been pregnant with when she suffered her stroke.

A guide Dahl created with the held of his neighbour was followed by many stroke patients, leading to the formation of UK charity, The Stroke Association.

In the end, what their marriage couldn't survive was Dahl's infidelity.

Then aged in his 50s, Dahl has began an affair with Felicity "Liccy" d'Abreu Crosland. After battling with his wife for years to gain permission to continue his affair within their marriage, the pair divorced in 1983. Shortly after, Dahl and Liccy married.

About seven years later, one last misfortune would befall Dahl. He developed a rare cancer of the blood, and died on 23 November 1990, aged 74.

Did you know anything about Roald Dahl's sad personal life?