Stewart is the hearth-goddess of the American home: a Delia Smith for the age of Madonna, but one whose taste-obsessed realm extends beyond the kitchen to embrace all aspects of "personal lifestyle" - from cooking and gardening to party-giving and home decorating. Stewart has been voted one of America's 20 most influential people by Time magazine. "It's a good thing" - a phrase Stewart used in a 1994 American Express commercial - is a household saying.
Her business empire, Martha Stewart Living Omnimedia, includes in its portfolio a weekly syndicated television show, watched by 5.5 million people, and a syndicated column ("Ask Martha") read by 200 million in North America. Then there's a mail-order company, royalties on her 12 books, including the bestsellers Entertaining and Martha Stewart Gardening, and her flagship magazine, Martha Stewart Living, which, with more than 2 million readers, is one of America's most successful publications.
Stewart began her climb to stardom as a caterer to Manhattan's rich and famous in the glitzy 1980s. By then she had begun to give birth to a family of cookbooks: Martha Stewart's Quick Cook, Martha Stewart's Hors D'Oeuvres, Martha Stewart's Pies and Tarts. All were immediate successes. All, it seemed, set new standards of excellence. They were well written, lavishly illustrated and beautifully produced. Her 1982 classic, Entertaining, now in its 29th edition, became the bible of the American dinner party. When, in 1991, in conjunction with Time Publishing, she brought out the first issue of Martha Stewart Living, it was almost hoovered off the racks. The magazine held out the promise - some would say illusion - that, even in the age of Beavis and Butthead, gracious living was possible in America.
While the country seemed to grow daily more crass and vulgar, Martha Stewart offered a nostalgic vision of domestic harmony straight from the pages of Little Women. As the big picture became more and more confusing, Martha Stewart Living devoted itself, almost Zen-like, to the small details of life: how to grow the perfect tomato, make balsamic vinegar, create an eye-catching floral centrepiece for the dinner table. And it was not for the brainless. Martha Stewart acolytes were well-educated, articulate, professional women who found in Living a comforting counter-balance to the bruising world of work.
Its editor and publisher knows all about that. Once described by a friend as more focused than a bullet in flight, Martha Stewart packs into one day more than most of us manage in a week. She sleeps four hours a night and, when she is not running her ever-expanding business empire, spends her time helicoptering between her homes in New York, East Hampton and Connecticut.
Born Martha Kostyra, of blue-collar Polish-Lithuanian origins, in Nutley, New Jersey, Stewart attended New York's prestigious Barnard College, where she majored in art history. Her stylish good looks won her work as a model; her early marriage to Andrew Stewart, a rising star in American publishing, gave her access to New York's literary and cultural scene and a "Waspy" surname that removed the stigma of her lowly, immigrant birth.
The defining moment of her early life seems to have come in 1964 when the Stewarts moved to a dilapidated schoolhouse without running water in Massachussetts. Martha was no hippy, though. Instead, she discovered her talent as a home-maker, gardener and purveyor of an aesthetic that deftly combined elegance and thrift. Driven by colossal ambition and an almost pathological inability to relax, she was to turn her skills into a $200m a year franchise. She showed American women, above all, how to have style without money. By combing yard sales and being inventive - her East Hampton house is full of candleholders made out of dried star fish spray-painted silver - they could make their homes as attractive and beautiful as Martha's. Like Ralph Lauren she plundered the style and taste of the class above her - the "old money", Wasp aristocracy of the East coast - and merchandised it to the masses.
The secret of her genius was to turn herself into the product. "Millions of women want to be Martha Stewart," Michael Shain, a writer with the New York Post and a Martha-watcher of many years, says. "She's the perfect entertainer, the perfect host, the perfect home-maker."
Her critics would argue that, by challenging American women to be as perfect as her, she is setting them an impossible task. What modern woman has the time to make transparent organdy cushion covers that give the impression of snow? Or hand-painted tablecloths for that perfect tea setting? Certainly not Martha Stewart. She has an army of helpers to do it for her.
Such facts do not deter her fans, among whom Stewart inspires an extraordinary degree of loyalty and affection. Many view her meteoric rise as a paradigm of the empowerment of women. When, in an audacious move in January this year, she bought back control of her entire franchise from Time Warner for $75m (pounds 47m), it seemed that this leggy blonde avatar of American capitalism could do no wrong.
But over the last few months her reputation has faced a series of attacks. First came an ugly feud with her East Hampton neighbour, a property tycoon called Harold Macklowe. The cause was an unfenced patch of "wetlands" dividing Travertine House, Stewart's 2,409-acre property in East Hampton from Macklowe's. According to Stewart, Macklowe had trespassed on to her part of the wetlands, planted 14 shrubs and erected "suburban" lighting fixtures.
The feud rumbled on all the way through 1996. "He (Macklowe) has taken my air, my light, my breeze," Stewart wailed to the State Supreme Court in Riverhead in August that year. Then, last May, in the highly publicised denouement, Stewart was alleged to have driven her Chevy Suburban into the Macklowe property and, having verbally assaulted his landscape gardener, reversed into him, pinning him against a fence and bruising his hip. It looked as if the guru of gracious living might end up in the slammer. In the end the police decided not to prosecute, but the case rumbles on, with Stewart likely to face a legal bill of $1m.
Worse came when an unauthorised biography appeared in the States. For millions of American women, Martha Stewart was the neighbour they dreamed of: the kind who drops by with a glue-gun and a smile, helps them bake a wedding cake or make that ugly old sofa look pretty. She was a role model in other ways: in her magazines and television shows, Martha would wax lyrical about the family and the sanctity of the home. But the image of her created in the pages of Jerry Oppenheimer's Just Desserts is very different.
The book makes a number of allegations which, if true, show the depths to which Martha and Andrew Stewart's relationship sunk before their divorce in 1989. One Mother's Day, her husband brought up a breakfast tray decorated with a rose. But something about the tray displeased Martha and, in a fit of anger, she threw it at him. Another time, the couple had a flat tyre during a stormy drive home from New York. Martha Stewart screamed at her husband that it was his fault for driving badly. When he got out of the car to change the tyre, she made him take off the expensive raincoat she had given him, so that he was soaked to the skin. When Andrew Stewart finally bailed out of the marriage she went ballistic.
From the age of three, Alexis Stewart, the couple's only child, appeared in numerous television and magazine shoots at her mother's side: the perfect girl in a pinafore dress. But at home, like many over-achievers, her mother had little time for her. If she came into the kitchen when mum was cooking, she risked being bawled out. The book contains a quote from an unnamed member of Stewart's staff who claims she witnessed Alexis sticking a knife in the kitchen table, saying, "I'm going to kill her someday."
In the aftermath of the messy breakup of the Stewarts' marriage, Oppenheimer alleges that Martha tried to buy her daughter's affection and loyalty with money and indulgence. Once, when Andrew Stewart was away at a publishers' meeting, Martha's secretary called him to say that something terrible had happened to Alexis. It was only a desperate ruse to make her ex-husband talk to her again.
The Oppenheimer book is based on interviews with hundreds of people who have worked with, or known, Stewart and presents a portrait of a woman many describe as "greedy" and "egomaniacal". Stewart, however, has called the book "a hideous piece of yellow journalism" and "crap" (the more extreme among her followers wanted itburned).
Some of her employees remember Martha Stewart as a dictatorial bully. Everything had to be spotlessly clean in the kitchen. If it wasn't, Stewart would let rip. "One time she came marching into the kitchen in her safari jacket," a former colleague recalls, "conducted an inspection, and discovered a couple of scratches and some marring on the stainless steel. She was furious, and everyone was scared to death. She came up to each of us. 'Who did this? I'm going to get to the bottom of this. Somebody's going to pay!'"
There were other accusations: that she used left-overs from one party as hors-d'oeuvres for the next, and borrowed another cook's recipes. And when food-testers from the New York Times tried some of Stewart's concoctions they discovered some serious errors.
Just Desserts comes at a particularly awkward moment because Martha Stewart is poised to scale yet another pinnacle with a new television show on CBS each morning which is expected to put her in the same league as Oprah Winfrey. There are more books planned, notably a lavish Martha Stewart's Christmas.
No one expects any of this to be derailed by Just Desserts. If anything, the book may end up enhancing her status. "In a way, the book is a sign of her coming of age, despite its contents," says Michael Shain. "It says, 'She's arrived'."