Weaving a tale of an old basket-case

The art of the literary biographer may be flourishing, but it is no golden age. Too often we are presented with postmodern reconstructions that mine scholarship for salacious and polemical purposes. Jonathan Swift, the legendary basket-case created ready-made by the Victorians, was always a treasure chest of neuroses waiting to be repackaged.

For Victoria Glendinning, historical knowledge of Swift is full of puzzles and mysteries to be unravelled and reknitted by the creative novelist: "I think it was like this...". Dedicated Swiftians will be unimpressed. Instead of a chronicle biography, Glendinning claims to have written an 18th-century-style "written portrait" as the best method to confront the "impossibly difficult questions" and "to speculate about their answers".

Glendinning's Swift is the latest addition to a long pedigree. As evidence for her centrepiece - the alleged marriage of Swift and Stella (Esther Johnson), and the parallel affair with Vanessa (Esther Vanhomrigh) - Glendinning goes back to contemporary sources, offering gossip and hearsay that appeared immediately after the satirist's death in 1745. The trouble with many of these sources is that they were written by a motley assortment of people with sometimes dubious motivations. They cannot be substantiated, yet Glendinning manipulates the evidence despite an equal number of important sources who did not believe Dublin "talk".

Her technique aims to heighten the plausibility of such gossip, her speculations achieving the feat of creating new variations before concluding that there is no evidence for or against all of the scenarios reconjured in her book. She constructs a flimsy potential for incest (Stella and Swift as progeny of their mentor Sir William Temple) as a barrier to the consummation of the marriage before informing the reader that the idea be dismissed. Finally, she concludes that "impossibly difficult questions" are just so, and we are left to ponder the riches of her speculations but left, ultimately, none the wiser.

Parallel to this, Glendinning sets out to deconstruct those 19th-century biographies that emblazon Swift as a moral monster, a scatological defamer of women, godless, obsessed with bodily functions and filth. Here she is more successful, showing that scatology represents only 3 per cent of the writings. Swift cleaned his teeth with a brush twice a day and bathed once a week - fanatically hygienic by the standards of most of his stinking peers.

Glendinning is excellent on 18th-century detail such as wig maintenance and sewage, and this enhances some vivid cameos. She is less successful in countering Victorian allegations of Swift's pathological problems with sex and women, settling for a subject with a "screwed-up attitude to women" rather than one who is so repulsed by sex that he could not possibly have "done it" with Vanessa.

Glendinning's drops into contemporary slang can often be disconcerting. To describe the author of A Modest Proposal as a "spin doctor" is an alarming reduction; there is the possibility that he believed much of what he asserted. She offers hardly any criticism of the works beyond general comparisons of Gulliver's Travels with The Borrowers and Quentin Tarantino's Reservoir Dogs . Somehow Glendinning's portrait of Swift debunks her own claim that he represents "moral true north".

Thom Henvey is completing a PhD on Swift at the University of Wales, Lampeter.