The Finkler Question, By Howard Jacobson

The American poet John Berryman famously recounts being abused as an "Imaginary Jew" by a drunken Irishman in the 1940s. Berryman's repeated denials that he was not a Jew, during the assault, only confirmed his supposed Semitic slipperiness in the eyes of his abuser. Looking back at the incident, Berryman concludes that what was "real" and what was "imagined" for his assailant were one and the same. Such confusions are the starting point for Howard Jacobson's tenth novel. But instead of a gifted poet, Jacobson's unreliable victim, Julian Treslove, turns out to be an all-purpose celebrity double and serial failure.

Treslove is attacked on his way back from dining with two of his oldest friends, Samuel Finkler and Libor Sevcik. Finkler was a schoolmate, who has turned into a life-long rival, and Sevcik (a "wizened European Jew") was their teacher and father-figure. Both of Treslove's companions are recently bereaved although "with their women gone, they could become young men again". Treslove feels doubly excluded from the group as a non-Jew (outside the internecine squabbling) and because his two ex-wives are still very much alive and kicking.

After his mugging by a woman, the forty-nine year old Treslove convinces himself that it was an anti-Semitic attack ("you Ju"). To compound his paranoia he begins to imitate his friends, as a born "chameleon", by thinking "Jewishly". Much of the novel's comedy surrounds the attempt of Treslove to resolve his "incomplete" identity - a "universal lookalike" – by becoming a Jew or "Finkler".

What is absurd about Treslove's philo-Semitism is that it has very little to do with actual Jews. After all, he was sacked from the BBC because he spoke in a "language of loss and sorrow" and feels himself imaginatively to be part of the "dispossessed" and "homeless". He also has a comically "tragic" view of women and names his estranged sons after characters in Italian operas. All of these lachrymose qualities can be thought of as "Jewish" but they are also something else entirely.

Finkler and Treslove are both sons of shopkeepers but they could not be more different. Treslove reveres women, Finkler is a mere womaniser. While Treslove is utterly disconnected from himself and the world, Finkler writes bestsellers such as The Socratic Flirt: How to Reason Your Way into a Better Sex Life. The more Treslove embraces Judaism, the more Finkler distances himself from his people (especially after Gaza). He joins "ASHamed Jews" which results in some heavy-handed parodies of his fellow-ASHamees.

In the second part of the novel, Treslove finds 'truelove' in the guise of Hephzibah Weizenbaum (saying her name is said to tire you out). She is both the most compelling voice in the novel and exposes Treslove's idealisations as just another form of anti-Semitism. Not that The Finkler Question, which has been long-listed for the Man Booker Prize, turns everyone into an anti-Semite.

While assaults on Jews proliferate throughout the novel, in a bleak undertow, Libor is well aware that dividing the contemporary world up into "Jews" and "anti-Semites" is profoundly dehumanising. The unedifying children in the novel seem especially prone to such black-and-white reductions. In the end, Hephzibah's sage scepticism - "was it something or was it nothing?" - wins through.

Treslove finally learns the difference between real and fantasised "tragedy" and between "love" and "envelopment". His passivity is replaced by farcical activism as he accuses his erstwhile people of ceding their "sense of outrage" and takes to the streets. Finkler's one-dimensional ambition and opportunism is also transformed by a deeper sense of what it is to mourn. The Finkler Question balances precariously a bleak moralising with life-affirming humour.

Bryan Cheyette is the Chair in Modern Literature at Reading University