THE SPARKLET was her nickname, and anyone who met her could tell why. Perhaps Scotland’s most important modern novelist, Muriel Spark was a small, striking woman, with a coruscating mind. She brought a vivacious imagination to her writing, backed by pitiless powers of observation. “You may not call Spark’s novels lifelike,” her fellow Scottish author Allan Massie once wrote, “but it is probable, even certain, that you will some day, sometimes, find life to be Sparklike.”

She wrote more than 20 novels, as well as stories, plays and children’s books, and was a master of taut, quirky plots, often focusing on a small group of people whose lives are altered by a strange twist of fate. She admired what she called a literature of ridicule — “the only honourable weapon we have left” — and even in her own social life, she said, she picked up the craft of being polite while people were present and leaving the laughter until later.

She made her name with the character of Miss Jean Brodie, the unconventional and incorrigibly romantic Edinburgh schoolmistress with an admiration for Mussolini and dedication to the crème de la crème of her pupils. A restrained comedy of manners, mocking the old Edinburgh politesse, The Prime of Miss Jean Brodie (1961) sold hundreds of thousands of copies. It was adapted for the Broadway stage and made into a film in which Maggie Smith took the schoolmistress’s starring role.

Spark wrote rapidly, rarely revising what she scribbled in the spiral-bound notebooks, which she had sent to her in consignments from the Edinburgh stationer’s James Thin. She claimed to have dreamt up The Public Image (1968) — about a film star’s struggle with the scandal industry — while asleep: “When I woke up every detail was in my head. I just wrote it all down.” In A Far Cry from Kensington (1988), she dispenses authorial advice. Write as if you are writing to a friend, she suggests. “Write privately, not publicly; without fear or timidity, right to the end of the letter . . . as if it was never going to be published, so that your true friend will read it over and over and then want more enchanting letters from you . . . Remember not to think of the reading public. It will put you off.”

In 1992 Spark published her autobiography, Curriculum Vitae, a series of vignettes and flashbacks of a life full of intriguing characters and peculiar subplots. But she detested intrusion into her private life, and the book tells very little about Spark herself. She could be prickly and had a reputation for falling out with friends and associates. A former editor, for example, with whom she once shared the ownership of a racehorse, fell from grace when he described her in an interview as “really quite batty”.

Muriel Spark was born Muriel Sarah Camberg in the genteel Edinburgh suburb of Morningside. Her father, Bernard Camberg, an engineer in a rubber factory, was a Jew whose family had settled in Scotland. Her mother, Sarah Uezzell, was an English Presbyterian from Watford, who was later to take to drink.

The religious divide in her parents’ marriage was to influence Spark’s imagination considerably. In her only long novel, The Mandelbaum Gate, set in Jerusalem during the trial of Eichmann, a Roman Catholic woman finds herself in peril because of her part-Jewish ancestry. In later life Spark was to become involved in a bitter feud with her son Robin (a painter) about her Jewishness, and the quarrel snowballed in a blizzard of birth and marriage certificates, claims and counterclaims. (Spark’s relationship with her son was not improved by her comments about his paintings: “He always wanted me to say they were good but I didn’t think they were”, she said. “Art is important to me and I’m not going to commit perjury.”

Spark’s native city remained very important to her. Wherever she went in her long life, its puritanical ethos remained with her, and her religious faith came to be symbolised by Edinburgh’s Castle Rock. “To have a great, primitive black crag rising up in the middle of populated streets of commerce, stately squares and winding closes,” she said, “is like a statement preceded by ‘nevertheless’. In the middle of worldly enterprises there is, nevertheless, the inescapable fact of God.”

At James Gillespie’s School for Girls, a merchant foundation where pupils started classical languages at seven, Spark encountered Miss Christina Kay, the inspirational teacher who was the model for Miss Jean Brodie. “She entered my imagination immediately. I started to write about her even then. Her accounts of her travels were gripping, fantastic,” Spark later wrote in her autobiography. “Her dazzling non-sequiturs filled my heart with joy.”

And Miss Kay encouraged Spark to write. She had written her first poem at nine — a version of The Pied Piper of Hamelin called The Piper Pied — and, being reared on the Border Ballads, she had a taste for a good yarn. By adolescence she was composing torrid love letters that she signed with fictitious men’s names and hid under the sofa cushions in the hope of shocking her mother.

On leaving school, she went briefly to a technical college, but in 1936 ran away on a romantic impulse to Salisbury in Southern Rhodesia to marry Sidney Oswald Spark, a schoolteacher more than 12 years her senior. “I don’t quite know why I married SOS,” she later said. “I suppose I was attracted to a man who brought me bunches of flowers when I had ’flu. But my husband was very much a nut.” He became increasingly quarrelsome and violent, often shooting his revolver at the walls.

Spark separated from him shortly after her son was born in 1938, and the marriage was later dissolved, although Spark kept the name because “it possessed some ingredient of life and fun”. She was never to marry again, and although there were several subsequent love affairs she was always “a very bad picker of men”, she said. “Maybe I was subconsciously protecting myself as I didn’t really want anything that rivalled my work in attraction,” she said.

In 1944 she returned to Britain and, depositing her seven-year-old son with her parents, took a room at a London club for “ladies of good families” — later to serve as a model for the boarding house in The Girls of Slender Means — and found work in the Political Intelligence Department at Woburn Abbey, where her creative talents were put to use inventing bogus news items for “black” propaganda broadcasts.