An unpublished short story from one of the 20th century’s greatest authors is appearing for the first time in the Strand magazine this week, offering the suggestion that Raymond Chandler suffered from previously unknown insecurities over his writing talents.

Nightmare is an intriguing vignette that portrays Chandler, creator of the gritty fictional private detective Philip Marlowe, on the wrong side of the law, in a cell on death row awaiting execution for murder.

The magazine’s managing editor, Andrew Gulli, described the tale as a “sleep-induced sojourn” that he discovered among a cache of papers belonging to Chandler’s secretary and later-life companion Jean Vounder-Davis. A collection of her possessions, including Chandler’s typewriter, and a number of poems and private letters he had written, was sold at auction in New York in December.

Gulli has previously uncovered lost, unknown or rarely seen creations from a range of prominent writers including Graham Greene, Truman Capote, HG Wells and Chandler, the Chicago-born, British-American author of classics such as The Big Sleep; Farewell, My Lovely; The Lady in the Lake; and The Long Goodbye. Chandler died in 1959 aged 70.

The personal story also features Chandler’s wife Cissy, who according to Gulli said she thought Nightmare was “very funny”. It means the story was written prior to her December 1954 death, but dating it precisely gets “tricky” beyond that, he said.

More notable, he said, was that the content of the short story, which Chandler probably never intended to be published. It suggests he might not have been as confident in his writing and self-promotion abilities as he liked to present.

“The most revealing line in Nightmare is Chandler’s aside: ‘It will remind me of the days when I used to get returned manuscripts’,” Gulli said.

“Chandler loved to mythologize his own life. In 1933 he told his friend William Lever that ‘I sold the very first story I sent out’. This was Blackmailers Don’t Shoot, published in Black Mask in December that year.

“Nightmare casts doubt over this. Did he submit stories to Black Mask before Blackmailers Don’t Shoot that were turned down? Or was he thinking back to his first literary ambitions in London, or to the years after the [first world] war when he worked in the oil industry?”

Gulli said it was “entirely plausible” that Chandler, who lived in London between 1900 and 1912 and became a British subject before returning to the US, had struggled to sell his writings before turning to full-time crime writing in the early 1930s after losing a job in the oil industry.

“Whatever the precise context, Nightmare complicates the neat origin story Chandler liked to tell,” Gulli said.

“It hints at a different and less successful literary trajectory. For all his efforts to make himself seem self-invented, Chandler remained, even to himself, his greatest mystery.”

Sarah Trott, a UK-based author of the Chandler biography War Noir, said the discovery of the story, among other authenticated papers in the Vounder-Davis collection including love letters to Cissy, helped expose an “incredibly sentimental” side to him.

“The publication of anything new by Chandler only makes him an even more multi-faceted writer. The more we uncover, the more complex he becomes,” she said.

“Whether it’s his crime novels, his short stories, or poetry, Chandler was a writer undoubtedly concerned by the human condition and many of the stories and vignettes uncovered over the past few years highlight just how he sought to understand human foibles, experiences, and emotions.

“Nightmare is interesting because on the surface it appears as a nightmare scenario, a man accused of a heinous crime that he can’t remember committing. The final bracketed sentence feels as though this is simply an account of a horrible dream, a literal nightmare.

“Yet the mention of Cissy, Chandler’s wife of 37 years, suggests this nightmare was an even more personal connection for the writer: the horror of rejection by publishers. We get to see the real Chandler … it feels more personal and intimate than the Marlowe novels.”