In the peace and quiet of her Inverness home, her tasks of looking after her ailing father done, the intensely private Elizabeth MacKintosh settled down to what she liked to call “my knitting”.

With her short, dark hair swept back in the kind of stern, no fuss style redolent of the PE teacher she once was, she carefully stitched the complex threads of her work together.

The calm Highland scenery outside her window must have provided sharp contrast to the dark tales that swirled around her imagination. For Elizabeth MacKintosh, a gentle Highland lady who had sacrificed her career to be her father’s career, had murder on her mind.

What she called her ‘knitting’ was, in fact, some of the most highly acclaimed crime thrillers both of their time and now; twisting tales that delved into the tormented human psyche and posed deep questions about what drives someone to kill.

It was a period that would go on to become known as the ‘golden age’ of crime writing – her contemporaries included Agatha Christie. But while Christie’s name remains synonymous even now with a ripping story of murder, crime and intrigue, Miss Mackintosh is far less known.

That is set to change – to some extent, at least - with, 60 years after her untimely death at the age of just 55, the culmination of a determined campaign for a commemorative blue plaque in her honour.

It will be installed at the end of next month, positioned on the site of what was once her family’s fruit shop and business in the heart of the town which she seldom left.

The most prominent name it will bear, however, is not the one that Miss MacKintosh’s Inverness friends, neighbours and relations would have normally used to address her.

Instead, perhaps in a curious echo of the fictional world in which she disappeared to write, the name in large capital letters across the plaque will read ‘Josephine Tey’.

For fans of a roaring early 20th century tale from a master of the art, news that a blue plaque dedicated to the most famous crime writer that many Scots have not even heard of, is long overdue.

It’s particularly poignant, for around the same time, her name will be further elevated thanks to a forthcoming exhibition at the National Library of Scotland, which will examine authors like MacKintosh who chose to mask their identity behind a fictional pen name.

The exhibition, ‘Pen Names’, at the library on George IV Bridge, Edinburgh, will use material from its extensive literary archives and printed collections to explore writers from the 1800s to the present day who opted to use pseudonyms – names such as George Eliot, Lewis Grassic Gibbon, Frank Quitely, T.L. Huchu, Ambrose Parry, Lewis Carroll and Josephine Tey.

While these days using an alias is perhaps more common than ever as people mask their true identity for online platforms using made up names, the exhibition examines the factors – privacy, gender, reputation and genre – which have influenced writers across the generations to adopt a fictional persona.

Yet the hugely talented Elizabeth had every reason to put her name to her work: her eight crime novels written under the name of Josephine Tey were highly acclaimed at a time when crime as a genre was at a peak.

One of them, The Daughter of Time, a highly original mystery based around murderous claims against Richard III set entirely around her fictional detective Inspector Alan Grant's hospital bed, went on to be voted the best crime novel of all time by the Crime Writers’ Association.

While from her home in Inverness she wrote a string of other successful novels spanning a range of genres and under more than one name. Her first play, Richard of Bordeaux, written as ‘Gordon Daviot’ in the 1930s – a name apparently chosen because of her fond memories of holidays in Daviot close by the River Nairn – was seized upon by the London glitterati.

It was immediately propelled to the West End stage starring Sir John Gielgud – who, oblivious to the writer’s identity, wrote to her addressing his letter to ‘Dear Gordon’.

Down the years her books have been adapted for radio, television and film - most notably by Alfred Hitchcock, who based his 1937 film, Young and Innocent, on Tey’s novel, ‘A Shilling For Candles’.

MacKintosh, however, remained unfazed by the praise for her work from the great and the good, preferring to avoid mixing with them in favour of her Highland home.

“She worked with people like Laurence Olivier, yet she never moved away from Inverness,” says her biographer, writer Jennifer Morag Henderson, who, along with the Inverness City Heritage Trust, led the campaign for a plaque at the town’s HHA Castle Street development on the site of MacKintosh’s family shop.

“She wanted to stay private and her life in Inverness gave her the time to write.

“I think using a pen name was part of her imaginative life.”

Born in Inverness in 1896, she was the eldest of three daughters for a Gaelic-speaking father who had left his Hebridean home for a new life on the mainland, and mother Josephine, whose name she would later adopt.

Her sights had been on a career of physical training – physiotherapy was an emerging skill which would become in high demand as a result of the First World War – which she combined with teaching at various locations in England and Scotland.

But life took an unplanned turn with her mother’s death in 1923, and her return to Inverness to look after her father.

“There’s an element that perhaps it was not the life she had chosen, but it gave her time to write and she made the best of it, creating these amazing imaginative stories,” adds Jennifer.

Her ability to weave an engrossing story meant she was in high demand for interviews, which she resiliently avoided, only enduring publicity photographs under duress.

That lack of interest in the celebrity world, her decision to leave her inheritance – including the rights to her books – to the National Trust in England, and those different pen names, meant that after death, her profile soon faded.

Kirsty McHugh, co-creator of the NLS Pen Names exhibition, which opens at the George IV Bridge library on Friday, July 8, said: “The stories of why authors use pen names and how and why they chose them are often as compelling as their books.

“Writing something and managing to get it published or performed on stage is something most writers want to shout about from the rooftops. They want their name on the cover, ideally as prominently as possible.

“So when they do choose to use a pen name, it’s often for very specific professional or personal reasons.”

Elizabeth MacKintosh died at her sister’s London home from liver cancer in 1952, having kept her illness secret from all but her closest connections.

“I believe a celebration of Tey’s life and work in her hometown is well deserved,” says Jennifer.

“She is a wonderful writer whose books have brought many hours of enjoyment to readers which is reflected in the critical, popular and lasting acclaim they have received.

“After months of campaigning for the installation of the blue plaque, it is incredibly exciting to help Tey’s legacy live on in the city.”