THE more novels one reads - and I read many more than is good for me - the more one realises how tired and bereft of fresh thinking the form is.

Its last truly significant development was in the early decades of the 20th century, when Joyce and Woolf, Proust and Kafka, freed it from its Victorian shackles and offered future novelists the freedom to roam as they pleased. Alas, their successors have too often proved themselves incapable or timid or wilfully experimental and, rather than looking outward in the hope of finding innovative ways to tell stories, they have turned inwards, writing novels about novelists writing novels. And, I fear, with the explosion of creative courses, the disease is destined to spread even further, not least because the lives of novelists - the material that is truly their own - are now so barren.

David Gilbert is the very model of a modern novelist. He is clever and knows his way around the bookshelves which, incidentally, is not something you can say about many of his peers, most of whom couldn't tell the difference between George Gissing and Georgette Heyer. He is as au fait with Pynchon and Barthelme and Nabokov as he is with Bellow and Updike and Roth, to all of whom there are nods in & Sons, his second novel, and all of whom, to a greater or lesser degree, influence its narrative posture. In that regard, Gilbert hopes to have his cake and eat it, playing realism off against post-modernism. One cannot, therefore, doubt his ambition. One can, however, question its effectiveness.

First, though, let us give praise where it is due. & Sons is that rare beast, a novel with a distinctive, compelling voice which is, a few bum notes aside, rather beautifully written and teasingly entertaining. Gilbert is the kind of writer not content with composing workaday sentences. You can't imagine him, for example, rat-tatting them out like Hemingway or Carver. For example, he doesn't allow someone to just smoke a joint, he must first clear a path to his beard. A woman who undresses in an apartment in full view of an adolescent seems "allergic" to shades. A first novel, meanwhile, is described as "a miscarriage of deformed autobiography".

Gilbert rolls out such images and phrases with metronomic regularity. Inevitably, then, he occasionally misfires or is guilty of trying too hard, as when one of his characters rises from his chair, "like Oscar Wilde playing Winston Churchill getting bad news from the front". Nor can he let someone simply think that rain may be on the way, his metaphorical "dowsing stick" must tell him so. One could go on but you get the point. It could be said of course that this - pace post-modernism - is deliberate, given that Gilbert's narrator, Philip Topping, is a would-be writer who is writing about AN Dyer, a writer contemporaneous with and almost as famous as JD Salinger, but I don't think so.

Dyer is coming to the end of his long life. He lives in New York in an apartment overlooking Central Park, "his Wailing Wall". He is the author of a number of celebrated books, none more so than Ampersand which vies with The Catcher In The Rye as a generational lodestar. As a movie producer who's keen to acquire the rights to it tells Philip, "I lost my literary virginity to that book." He is not alone. But it's one among a number of books which their authors come to feel ambivalent towards. Having sold in the millions, Ampersand is the one novel of Dyer's which everyone in America has read. Even now, as he senses death sharpening his sickle, he is furiously typing a copy of it to pass off as the original manuscript to the Morgan Library which is eager to acquire it for its collection.

For its first 200 or so pages, & Sons is effervescently, enjoyably conventional. Dyer has three sons, two by his wife, another apparently the result of an affair which cost him his marriage. The entire second half of the novel hinges on that "apparently". Each of the sons - Richard, Jamie and Andy - has inherited traits from the father - narcissism, boundless wit, a need to make a mark - which are the by-product of fame. It is Andy, the half-brother, however, about whom Dyer is most concerned and on whose behalf he engineers a rare family reunion, his intention being to ensure that when he shuffles off Andy will have support. It is the kind of situation for which Dickens drew the template. But what happens next makes the scene in Bleak House, when Krook, the rag and bone man, is made a victim of human spontaneous combustion, seem natural.

I dare not say more. Thereafter, however, & Sons loses a layer of sheen and much of its credibility. Rarely has one come across such a chasmic shift in a novel's direction, and been so disappointed. Dyer himself seems to speak for Gilbert when he tells his two elder sons how much he feels disenchanted by his chosen career. "Did I ever do it for the right reasons?" he says. "Mostly I just wanted to steer clear of lawyering and banking and politicking, the normal trades of my people. I needed to be unique. An unpredictable line rather than another circle. But it wasn't in my soul. Maybe a little bit in my soul. Mostly it just seemed like fun to focus on imagined things."

Which is fine as far as it goes. But is it enough justification for a lifetime's toil at the literary coalface?