Everybody knows the story of Scott and Zelda Fitzgerald: the wild, beautiful couple who named and encapsulated the Jazz Age, "the greatest, gaudiest spree in history". Blessed with talent, looks, love and money, they took all they could from life, never counting the cost; indeed, almost challenging someone, something, to check them. And so it did. By the time Scott was 30, he was an alcoholic, barely able even to write unsupported by gin; and by the time Zelda was 30, four years later, she had been institutionalised for madness, later diagnosed as schizophrenia.

Kendall Taylor asserts that what destroyed them both was Scott Fitzgerald's use of his wife's life as writing material. "Cunningly controlling", as Taylor describes him, Fitzgerald apparently shamelessly exploited Zelda's creativity, precipitating her downfall as he sought to realise his own artistic potential at the expense of hers.

Apart from any other criticisms, this is an anachronistic view. Taylor concludes with a long paragraph about which modern medicines might have helped Zelda, "who had used up her life providing material for a writer who to this day is considered one of America's greatest".

Taylor clearly does not believe that Fitzgerald was a great writer. At no point in the book does she attempt a critical analysis of his work. She also seems oblivious to the truth that, in 1920, when Scott and Zelda married, women, with very few exceptions, did not have careers. This does not mitigate Zelda's later attempts to achieve something of her own - but it does mean that it wasn't just a "controlling" husband she was struggling against, but a panoply of social and cultural assumptions. Finally, although Zelda's schizophrenia is treated throughout with sympathetic gravity, Scott's alcoholism is dismissed as merely "congenital", and his nervous breakdown accorded scant attention. This is not a portrait of a marriage; it's a defence of one party.

Like Nancy Milford, whose ground-breaking feminist biography of Zelda Fitzgerald was published in 1970, Taylor sets out to tell Zelda's side of the story, and her fruitless "struggle to succeed on her own". "Her Herculean effort to become her own person, to identify and do valuable work, love whom and how she pleased, and escape from being F Scott Fitzgerald's wife and model for his heroines . . . ended in madness," Taylor writes. "The only way out was through the insanity to which her family was prone."

This conclusion is patently naive, though it does not make the book less readable. Anything written on the Fitzgeralds is interesting - particularly a work as thoroughly researched and passionately conceived as this. But the whole foundation underpinning Taylor's argument is untenable. Scott is always presented as the villain, Zelda always the victim. Life is never that simple.

Scott and Zelda Fitzgerald were a dazzling couple: he with his promise and grace, his ability to make everyone around him feel as if something exciting was just about to happen; Zelda, "caresser of her own dreams", brave and tragic like a "barbarian princess", her eyes "full of cool secrets" - all this counterposed by the impression she gave of wearing nothing beneath her dress.

Initially, their union was a philosophy they accepted with all the narcissism of youth: they were soulmates, with shared dreams, shared values, alone against the world. Marriage would be their joint performance, "the live, lovely, glamorous performance, and the world shall be the scenery". But for all their public fame and private intimacy, the Fitzgeralds were always set on a path to self-destruction. Their marriage was a "folie a deux". As they both admitted, no one could have survived it. "Liquor on my mouth is sweet to her," wrote Scott. "I cherish her most extravagant hallucinations."

Conflict arose between them early. In order to afford the lifestyle he needed to keep Zelda, Fitzgerald wrote magazine stories, which paid far better than the great literary novels he hoped to write. "It costs more to ride on the top of taxis," wrote Zelda. Max Perkins, Fitzgerald's editor, saw it with a less romantic eye. He thought Zelda "kept him [Fitzgerald] writing for the magazines . . . she wanted everything". Zelda also demanded all Scott's attention, and was derisory of his often feeble attempts to work. The situation was aggravated by their heavy drinking. For Scott, alcohol was a way to escape the knowledge that he was wasting his talent by writing for magazines. For Zelda, alcohol was a way to retain Scott's attention.

Their friend Gerald Murphy described them in 1925 as inseparable, "a pair of conspirators": "It was as though they were waiting for something to happen: they didn't want entertainment, or exotic food; they seemed to be looking forward to something fantastic . . . Something had to happen, something extravagant. It was that they were in search of, and they went for it alone." If they couldn't have the intensity of happiness all the time, then they would have intensity of some other kind.

Taylor holds that it was Fitzgerald's use of Zelda in his fiction, and his refusal to allow her to write fiction herself, that destroyed her. There is some truth in this theory. According to Taylor, Zelda succumbed to madness because Fitzgerald, having used her in his books - often quoting directly from her diaries and letters - could not accept her desire to be someone other than just his heroine.

But if Zelda was Scott's muse, then he was her priest - and the qualities that made him worship her did not necessarily make her loveable. He was tortured, for instance, by Zelda's assertion that she could be physically unfaithful to him and remain untouched by it. The selfishness he loved in her, the attitude of taking what one wanted when one wanted it and never thinking of the consequences, contributed to their joint decline, as did Scott's hypocritical attitude to Zelda's writing. But, in the end, it comes down to the work: we are interested in Scott Fitzgerald not because he lived wildly, but because he wrote The Great Gatsby and Tender is the Night.

Lucy Moore is a historian