Sometimes the best nightmares are old-fashioned ones

Post-modernism is all very well, says Geoff Dyer, but you can't beat a thrilling tale well told; Hallucinating Foucault by Patricia Duncker Serpent's Tail, pounds 8.99

It has always struck me as perverse that anyone should write a thesis about an author they love. Putting someone through the academic meat-grinder like that is an exercise in mutual attrition. Researchers are obliged to grind their authors down and to wear themselves out in the process, and only when there is nothing left but dust, only then - by a final, exquisite irony - can they be called "Doctors". "Morticians" would be a better title, for they turn literature into a vast morgue.

Patricia Duncker's challenging, provocative first novel is about an apprentice- mortician coming alive to his subject and, in the process, bringing him back from the dead. The narrator is doing graduate work on a subversive French novelist, Paul Michel. He's content beavering and footnoting away in the library until he begins an affair with another graduate student, a bony, myopic, DM-wearing Germanist whose thick glasses - this detail proves crucial to the novel's symbolic scheme - give her the look of an owl. Yes, not my cup of tea either, but she blows apart the narrator's ideas of dispassionate, scholarly scrutiny of the texts.

Michel, she reveals, is mad, and for the last 25 years has been banged up in asylums in France. Goaded by his lover's intellectual passion, the narrator pledges himself to go to France, not just to find out what has happened to Michel in the intervening years but, also, if possible, to free him.

In doing so, he embraces the challenge set out by Foucault in the Preface to The Archaeology of Knowledge: "There are times in life when the question of knowing if one can think differently than one thinks and perceive differently than one sees is absolutely necessary if one is to go looking and reflecting at all." When he gets to the asylum where Michel is confined, the novel moves deep into Foucaultian territory, into themes of "madness, death, sexuality and crime" that attracted le grand philosophe. These were Michel's themes, too, and the books of the two writers constitute - it is claimed - a trans-generic dialogue, a series of mutually explicating, explicit yet allusive love letters.

We don't come face to face with Michel until past the novel's halfway point. Up until then we follow an archival trail that yields glimpses of his writing. Technically, Duncker thereby sets herself the problem directors have when making films about great imaginary artists: producing samples of work that live up to the myth created by the fiction. Michel's prose was "ironic, disengaged, detached", and the bits and pieces we see are enough to persuade us, just, that their (alleged) author was capable of writing the books on which his notoriety rests. Duncker succeeds in doing this partly through the contrast with the narrator's voice which, at times, suffers from the unengaging wobbliness befitting a 23-year-old graduate student. Early on, he nearly has a "brain haemorrhage with jealousy"; in Paris the streets stink of "Gauloises and urine"; later, he smokes so much that his mouth tastes "like an ashtray".

At this stage one is willing to give Duncker the benefit of the doubt, for an even more difficult feat is still to come: that of making the real- life - ie fictive - Michel live up to expectations. The suspense feels somewhat narrator-contrived, narrator-led: to make sure we are excited about the forthcoming encounter, the narrator is always telling us that he is "terrified", "seething", "shaking, his skin tingling." One is reminded of Leavis's point about Conrad over-doing the atmospherics on the way to the meeting with Kurtz. In Duncker's case, the anxiety and suspense felt by the reader is more far-reaching than the author intended: what we are also wondering is: will she pull it off?

She does. Michel crackles with electricity. The air hums around this compound and distillation of Artaud-Genet. The reader falls for his warped tenderness, his perverse saintliness. In his every move there is a latent propensity for violence, a memory and premonition of "madness or despair". That was what Marlow said of Kurtz, of course, but Michel has inhabited a world more terrifying than that suggested by the horror of jungle metaphysics. "He looked up into the trees. Then he said, quietly, 'You cannot imagine the horror of dailiness.' " Hallucinating Foucault is cunning, post-modern and so forth, but one ends up believing in Duncker as a novelist for the simple, old-fashioned reason that she has made us believe in her seething, wounded creation.