Lunar Park, by Bret Easton Ellis

He tells us about the highs and lows of being a Brat Pack author, about fellow writers Jay McInerney and Tama Janowitz, and describes how, at the height of his fame, he was invited backstage by Bono, Michael Stipe, Def Leppard and members of Bruce Springsteen's E Street Band. He reminds us of the commercial success of Less Than Zero and American Psycho, and emphasises their cultural importance. He confesses The Rules of Attraction was hastily written, and suggests that Glamorama mainly owed its success to the sex and gore scenes that appeased his fan-base. He writes about his problems with drink and drugs, and the debauchery that accompanied the Glamorama tour.

The early part of this novel most resembles Elizabeth Wurtzel's More, Now, Again, a similar account of coke binges between public readings. The only difference between Wurtzel's memoir and Ellis's novel is that while Ellis insists "every word is true," he is playing games from the first sentence.

What seemed to trouble critics most about American Psycho was whether or not the violent events in the novel were Patrick Bateman's fantasy. For the most part critics who enjoyed the book (such as the late Elizabeth Young) believed that Bateman's tale was a fantasy, while those who took the book at face value seemed deeply upset. In the past, Ellis has seemed to want to maintain the possibility of both interpretations, and this appeared to be one reason he was hinting at for not enjoying Mary Harron's film version of American Psycho as much as Roger Avary's more faithful, if updated, take on The Rules of Attraction.

Here in Lunar Park, he suggests "Patrick Bateman was a notoriously unreliable narrator and if you actually read the book you could come away doubting that these crimes had even occurred". That comes suspiciously close to a retrospective apology. Except the "Bret Easton Ellis" of Lunar Park is no more reliable a narrator than Bateman.

In fact, he seems far more insane. It's not just the egomania, the drugs or delusions (he believes that his daughter's toy bird is able to urinate and capable of carrying out attacks on his family); every sentence suggests only the most slender grasp on reality. Almost nothing he writes can be taken seriously, no matter how hard he tries to convince us he is telling the truth.

This combination of fiction and reality is mostly used for comic effect. Alongside people we know to be real (Ellis's guests at a suburban house party include Jay McInerney, David Duchovny and cast members from the TV show Survivor), there are characters who are supposedly famous yet clearly don't exist, such as Ellis's wife, the actress Jayne Dennis, who appears in imaginary films with Keanu Reeves.

Lunar Park is also filled with sly jokes and references that reveal the careful construction of this supposedly true tale. Bret lives on Elsinore Lane, both a play on his surname and a hint that this is a Hamlet story as much as a horror novel; his dog Victor seems named after the protagonist of Glamorama, underlining Ellis's harsh critique of his own fourth book.

In the past Ellis has seemed proud of his avoidance of plot, or rather, his clever questioning of what is required from a novel. He has created a style entirely his own, a world away from the work of McInerney or Janowitz, who are essentially very traditional writers. While this has always been instinctually understood by Ellis's fans, the American critical establishment have given him a relatively hard time: in Lunar Park, Ellis offers this as one justification for his drink-and-drug problem.

Here he separates himself from his persona, and moves away from his usual territory to explore suburban gothic. Bret moves to a big house in a nice neighbourhood, marries an actress with whom he has a child several years before, and works on a pornographic thriller called Teenage Pussy. As much as he tries to fit into this new life, he's haunted by visions of his dead father, who appears to be acting out the murders from American Psycho and the disappearance of a number of teenage boys, a happening he's convinced his son is somehow involved with.

The author Ellis seems to be emulating most closely (and one of the few writers he confesses to be inspired by) is Stephen King. In many ways this reads like a variant on King's "writer" novels, from The Shining (which gets an explicit name-check) to Bag of Bones. Like King, he is interested in fathers and authors; fictional creations becoming real; the presence of horror tropes as symbols for drink and drug use; Halloween; and the fear that, although the derangement of the mind is necessary for good writing, it can ultimately lead to murder and madness. Both authors also, in their later work, seem to be dealing with the aftermath of having achieved their fortunes through dwelling on the dark side.

Ellis also jokingly borrows from The Amityville Horror, Ghostbusters, Poltergeist and The Exorcist, revealing that he hasn't entirely lost his Eighties sensibility. His music tastes are stuck in the same decade, a deliberate joke and a way of making him seem out of touch with his kids. But as with American Psycho, there's an existential steeliness to his tone alien to the more folksy King.

Lunar Park is an enormously entertaining novel, powered by a celebratory fun entirely absent in the writing of the generation of American writers who succeeded Ellis. Far less hardcore than anything he has written so far, it's the novel that all his detractors should read, if only to discover that in spite of all the hype, the only person really damaged by American Psycho was - if we are to believe a word he says - Ellis himself.

Matt Thorne's novel 'Cherry' is published in paperback by Phoenix