Along a dusty stretch of the Caledonian Road in north London, PW dodges traffic, trying to find the way to Matisse biographer Hilary Spurling's house. The Caledonian Road runs between the bohemian flea-market maze of Camden Market and 1960s housing projects; streets of gracious 19th-century houses spiral off the area's arterial roads. On one of these quiet back streets, Spurling's house appears at last, its substantial Victorian facade livened by slightly eccentric architectural flourishes.

Settling down in Spurling's tranquil, secluded garden, under leafy trees and amid tumbling roses, PW remarks on a bust among the shrubs and a beautifully patinated piece of modern sculpture in one corner. Spurling, whose manner is quiet but engaging, intense and humorous, clearly has an eye for detail. Dressed in a dusky lilac silk jersey top and neutral trousers, she reveals a taste for discreet luxury of which Matisse would certainly have approved. The writer and her husband, playwright and art critic John Spurling, have surrounded themselves with an exquisite collection of paintings, etchings and drawings, each with a history. Inside, Indian miniatures share wall space with abstract art by contemporaries Paul Huxley and Bridget Riley, whose fascination with color led Hilary Spurling to explore the figure of Henri Matisse.

The first volume of Spurling's groundbreaking biography of the great artist, The Unknown Matisse, appeared in 1998, published by Knopf; it was selected by the New York Times as one of the notable books of the year. Now, an offshoot of that monumental work is winning acclaim on both sides of the Atlantic. La Grande Therese : The Greatest Swindle of the Century (HarperCollins), the novella-like biography of a glamorous 19th-century con artist, grew out of Spurling's Matisse research. Therese Humbert was only a bit player in the painter's biography, but her story threatened to burst the bounds of the small space she was allotted. "I had to fight so hard to relegate Therese to a minor role that, once the first volume of Matisse was finished, I felt I owed her a book of her own," Spurling says. Given free rein in La Grande Therese, the tale cracks along at the pace of a thriller, though it is as meticulous and scholarly as all Spurling's work. Its heroine has made such an impact that the BBC has optioned the book for a feature film, and a radio dramatization is planned as well.

Spurling talks with excitement about coming upon Therese's story on a visit to Toulouse in southwest France, where she had gone to research Matisse's wife's family. Though Matisse was reputed to be a dull man who lived a quiet life, Spurling discovered that in his early years as a painter he was embroiled, through his parents-in-law, in a scandal that rocked the French government. Matisse's father-in-law, Armand Parayre, was a socialist and idealist who became part of the household of Senator Humbert, who was Minister of Justice in the Third Republic. Parayre subsequently worked for Humbert's son and daughter-in-law, Therese. When Spurling tracked down Humbert's magnificent tomb in the village churchyard, the local priestput her in touch with an old villager who hinted at a story so big that it would almost blow Matisse out of the water. "That first encounter sent me straight to the departmental reference library in Toulouse to find out more about Therese. I settled down with archive copies of the famous radical paper La Depeche and turned the pages with mounting incredulity."

Therese was descended from humble village stock and as a girl would entertain her friends and neighbors with wonderful stories of chateaus and fortunes won and lost; soon she would engineer her own life to mirror her fantasies. At 17 she announced her engagement to the son of a shipping magnate. It was only after an elaborate handmade trousseau had been delivered that the whole thing was called off. After she married Senator Humbert's son, the senator was taken in by her tales of family riches and arranged to mortgage her nonexistent Chateau de Marcotte for the equivalent of 1.5 million British pounds.

Therese's staggering deceptions snowballed after she set up court in Paris. She announced that an American billionaire, Crawford, had named her as his sole heiress, in a will that was apparently being contested by two nephews. Therese kept the will and its many codicils in a strongbox at her new residence off the Champs Elysees, along with a hundred million francs in bearer bonds. The interest on these bonds provided the Humberts with their income and allowed them to borrow fantastic sums while the will was being fought over. Spurling describes the legal maneuverings with admirable clarity and dexterity.

For nearly a generation Therese entertained the great and the good of le tout Paris, including presidents, politicians and police chiefs. One of the joys of this small volume is its use of contemporary illustrations, from caricatures to police mug shots. In a drawing of a splendid dinner party where Therese is entertaining law enforcement officials, the centerpiece on the table is a chocolate replica of the famous strongbox. But it wasn't long before police officers were entertaining Therese. Senator Humbert died in 1894 and without his fine legal mind behind operations, Therese's schemes swung out of control. After a theatrical court case, Therese and Frederic were sentenced to five years imprisonment with hard labor. Therese was never heard from again.

La Grande Therese's British publisher is Andrew Franklin, who worked with Spurling at Penguin on her first Matisse volume. Franklin set up Profile Books and published La Grande Therese last fall in grand style, invoking the spirit of la belle epoque. Therese was particularly noted for her vertiginous millinery, and at the book party, Hilary Spurling appeared in an elegant hat with a spotted veil. Spurling now always wears the hat when she gives a talk about Therese , as she says that it enlivens her take on an altogether more exotic persona.

Even without the hat, Spurling can be dramatic when she wants. Her family history, particularly the tale of her birth, makes for good storytelling. She was born in Bristol on Christmas day 1940 during a bombing raid of the Second World War. "My father had been called up, and he went off to fight leaving my mother and me in Bristol. It was one of the most heavily bombed cities in the country. My infant memories are of bombs and my wonderful Mickey Mouse gas mask. That was a great pleasure. It was a very safe period to grow up. Everybody was so traumatized by the war that we had a freedom that is unimaginable now.

"I think that both my grandfathers were bankrupts. I know my mother's father was. He had been driven out by the Troubles in Ireland, and his life ended horribly. My mother was the first of the family born in Manchester, and because her father was then bankrupted, the family lived a very difficult life, of great poverty and great shame. My father's family were Scottish. Manchester was a place like that, it was a melting pot. Both sides of my family were people who didn't make it."
But Spurling's parents were determined not to carry on in the same vein. "My parents fled away from Manchester and cut themselves off from their families. My father had a post at Bristol University teaching law, like Gustave Humbert, I now see. My parents both escaped through university." Spurling's father studied law at Oxford, her mother history at London University.

Themes of social and economic vulnerability haunt Spurling's biographies, particularly her study of Paul Scott, author of The Raj Quartet (TheJewel in the Crown is the first volume of four in the quartet), published by Norton in 1991. Spurling also uncovered profound secrets here, of a nature so upsetting to Scott's family that she considered abandoning the project. Her agent, Bruce Hunter at David Higham Associates, had known Paul Scott and counseled her to persevere. Her painstaking research revealed that there was a gap in Scott's life, a period that was never talked about, that lasted nearly two years. Spurling tracked down the wife of Scott's closest friend from this period and discovered that Scott was homosexual, but had decided to conceal the fact. In the end, the delicacy and compassion with which Spurling dealt with this brought about a therapeutic resolution for Scott's family.

Spurling describes her working method as much turning over of stones, and she certainly turned over the crucial ones in the cases of Scott and Matisse. She researches by assiduously collecting evidence--which would make her barrister father proud--with academic thoroughness, a product of her own Oxford training. "I studied English and it was quite a disciplined education, I realize in retrospect. We began with Anglo-Saxon and we read Virgil in the original. Oxford to me represented escape. At school, we had been groomed to marry, we would have our hands in the washing-up bowl and the nappy bucket, and that was it. It felt like a death sentence. Both of my parents believed in education for girls, otherwise I could never have done it. Oxford opened the door, like it did for my father."

Spurling's fascination with modern art started early. Working for the British Council as a recent university graduate in the early 1960s, she saved up to buy a picture "that was the first picture we [she and her husband] ever bought. It was a painting by Paul Feiler, a St. Ives artist. That was all I knew about modern painting then. There was no modern art at home in the Bristol Art Museum, and you couldn't find out about it. It was only when I started working in London that I began to go to the Whitechapel [art gallery] and find out about abstraction and modern art."

Despite her longstanding interest in art, Spurling had to be convinced to write her massive biography of Matisse. Richard Cohen, her longtime editor and friend now based in Manhattan, finally cajoled her into committing to the project, although it took him 12 months. He has worked with Spurling for 14 years and met her when she was about to embark on the second volume of her biography of Ivy Compton-Burnett, Secrets of a Woman's Heart (1984). Spurling had published the first volume with Livia Gollancz in 1974 and had tried to renegotiate a larger advance for the second book. Gollancz refused, saying that all Spurling needed was a room and some carrots. Spurling countered that she now had two small children; were they to live on carrots as well?

Cohen whisked her off to Hodder & Stoughton, where he was editorial director. Spurling later moved with him to Hutchinson, where Paul Scott and Elinor Fettiplace's Receipt Book (1986) were published. The Unknown Matisse was bought by Hamish Hamilton with a clause naming Cohen as editor. Cohen had commissioned and published Glendenning's Trollope and Richard Holmes's Coleridge biographies and evidently has a genius for bringing out the best in biographers. Spurling particularly admires Holmes's erudite and passionate books. She has said of his work: "No one pleads a case more eloquently than Holmes, with greater delicacy of feeling, sharper humor or bolder intellectual daring."

Spurling first began to shape her own polished style as a theater critic and literary editor for The Spectator magazine (1964-1970). Since she's left journalism, she has had time to hone her phrases and produce her trademark subtle, balanced prose. "Using a computer has transformed my life," she says. "If you are a terrific perfectionist, which in my books I am, it speeds up that process immensely and you can experiment. I think that the computer matches the brain in a way that the typewriter can't. To go back to using a typewriter would be like going back to a tank when you had been used to driving a Maserati."

Spurling expects that the second volume of Matisse's life will take some years to complete. It took her five years, after all, just to research the first volume. But for a writer who sees research as a kind of treasure hunt, each day promises thrilling new discoveries that can change the way she looks at people and things.

Doran is a journalist and writer living in Tunbridge Wells, Kent, England.