Few female figures of the 20th century are more iconic than Princess Di. The dust jacket of this book, showing a black-and-white photo of a tiara'd blonde in a strapless white gown and pearls --- virtually copying a 1997 People magazine cover --- is immediately recognizable, though the model's face is turned away. Her innocence as a bride, her struggles as a wife, her escapades and good works as a divorced woman, and of course her untimely death add up to a bitter modern fairy tale. Monica Ali has rewritten that narrative and come up with a provocative alternative.

It's gripping, that's for sure. I ripped through UNTOLD STORY in a single day.

UNTOLD STORY has already stirred controversy upon its publication in the UK. The furor isn't about the book itself, which is clever and absorbing but neither scandalous nor earthshaking. It's about the author: Ali is a Bangladesh-born, London-based writer of serious fiction; her novel BRICK LANE was shortlisted for the Man Booker Prize in 2003. To some critics, this more commercial project is a betrayal of her talent.

I don't believe it's mere opportunism. I think Ali's impulse to write about a Diana-like figure came from the heart. I didn't grow up with the princess; I was already 36 when she and Charles were married. But for Ali, now 43 --- seven years younger than Diana --- perhaps she was a mirror of sorts, the way Jane Fonda (Hollywood royalty!) was for my age group. The identification was and is powerful. "What I've always admired about [Diana] is the way she simply refused to be told what to do," Ali said in an interview with a British paper. "She broke all manner of rules, she stuck two fingers up to the establishment --- she was a gorgeous bundle of trouble." Ali also insisted that UNTOLD STORY is no different from her previous work: "All my books are about identity, about what makes a person who they are."

Yet it would be naïve to suppose that Ali doesn't know that a Di-themed book is almost certain to reach a vast audience and make tons of money. I'm not saying she's insincere; I'm saying she can't possibly have been unaware that the novel had the makings of a bestseller.

The premise of UNTOLD STORY is that a certain nameless English princess didn't actually die. Harassed by constant media attention while simultaneously inviting it, she barely survives a car crash in Paris (irony of ironies), then decides to simulate a fatal swimming accident. She will go down near a yacht anchored in shark-ridden waters, so it is plausible that her body won't be found. The location is the Brazilian coast, convenient to the chicest plastic surgeons.

The plot is masterminded by Lawrence Standing, her Oxford-educated private secretary. Ali's best creation, he speaks to us via diary entries from 1998 that document the entire scheme and its denouement. Bookish, wry, sad and besotted with his boss, he organizes her escape like a four-star general. The most poignant aspect of the story is the princess's decision to leave her sons --- made even more touching by the recent sight of Prince William marrying his Kate. (The timing wasn't planned, Ali has said, but it seems a little too good to be true.)

Standing, sadly, does not make it through the whole novel; diagnosed with a terminal illness, he dies before a planned visit to the princess, now known as Lydia, in her new home. The United States seems the perfect place for her to settle: "Self-invention was American as applesauce." (Uh --- shouldn't that be apple pie?) After several moves, Lydia winds up in the Southern town of Kensington (more irony: Her former residence was KP, or Kensington Palace).

As UNTOLD STORY begins, it is 2007 and Lydia has lived in Kensington for nearly a decade (Standing's diary is a flashback). She works at a dog rescue shelter; swims laps in her pool; has a boyfriend, Carson, who is an insurance claims adjuster, and a group of devoted girlfriends. The only flaws are that she misses her sons and feels she is holding out on her American friends, all of whom are preternaturally kind, attractive and tolerant. Although she is a veteran teller of half-truths ("Lydia had done this professionally for a large part of her adult life --- given moments to strangers that they treasured as candid and intimate, not knowing her at all"), the lies make her uneasy. She is tempted to spill the beans.

Then John Grabowski, a rather sleazy paparazzo from Lydia's glory days, wanders into Kensington. He is snapping pictures of everyday America while working desultorily on a book slated for the 10th anniversary of the princess's death, a collection of unpublished images from his "private archive." Although Lydia's features have been surgically altered, to a guy with a state-of-the-art zoom lens her brilliant eyes are all too recognizable. Grabowski's pursuit of his quarry is a suspenseful cat-and-mouse game.

It's gripping, that's for sure. I ripped through UNTOLD STORY in a single day. There's no doubt that it is successful popular fiction, but does it transcend that genre? Not really. A lot of the supporting characters are out of central casting, and though Lydia herself, and above all Lawrence Standing, hint at greater complexity, they don't make you gasp and churn and see the world afresh the way the best and deepest novels do.

Still, at the end, when Lydia goes to a friend's lakeside cabin to ponder her next move, there is a change in mood that takes UNTOLD STORY to a more interesting place. In solitude, the ex-princess scours the house from top to bottom (the description of her cleaning is curiously satisfying) and then, while debating her future --- call Carson? turn herself in? leave Kensington for good? --- starts reading one of the only two books in the cabin, Solzhenitsyn's One Day in the Life of Ivan Denisovich (this is a woman who describes herself as having been "thick as a plank" in school). She is riveted. The message is clear: She has been a prisoner of her past.

There is always the hope that Diana herself would have managed to break free of the fame cycle and lay claim to a freer, more private life. Ali's book is a sort of pavane for a dead princess. It suggests that she was not simply a victim but, potentially, the heroine of her own story.