The unreliable I

A MAN in a supermarket car-park is shot in the back of the head. There is no motive and no witness. The last thing he sees is the tomatoes bouncing out of his bag, tomatoes which adorn the book jacket. A single bullet - "a severe insult to the brain" - has destroyed his occipital cortex, the lobes which make sense of visual data. Martin Blom's eyes dilate and contract in response to light, but what they perceive is not recorded in his brain. Lucky Martin: one millimetre either way and he would have been killed, and lucky us, for he is a spectacularly chilling example of the unreliable narrator.

Another writer might have made this a tale of endurance and rehabilitation, but Thomson's more playful concerns enmesh a find-the-girl thriller with epistemological anxieties and a dazzling authorial malice. Visser, Martin's neurosurgeon, explains that because the eyes still function, people who suffer from cortical blindness often believe, despite proof to the contrary, that they can still see. "I didn't know what was meant by proof to the contrary. 'Oh, falling downstairs,' he said, 'bumping into furniture - that kind of thing.' "

Blom makes a rapid recovery, with no apparent sign of the depression and delusions which, he is warned, plague the suddenly blinded. Cunning, he keeps to himself the fact that he can see - a realisation which occurs in the hospital garden when he is out practising with his white cane. His new vision, though fitful, can be painfully acute - the detective who comes to talk to him about the shooting has "teeth that were ridged, like celery" - and he discovers that he focuses best of all at night. Discharging himself, he tiptaps into film noir territory by spurning his embarrassed friends and embarking on a new, anonymous life. Despite a great deal of falling downstairs, bumping into furniture, that kind of thing, we have no choice but to believe the record of Martin's perceptions.

However, his vividly described nocturnal adventures are sufficiently weird to cause us doubt; they take him fearlessly into strip clubs and dingy rooming houses, cafes and lonely streets, bringing him into contact with a suspiciously surreal cast of exotic dancers, criminals and circus performers. At one stage he even joins the hunt for the Invisible Man. In his desperate search for his missing girlfriend, Nina, he borrows a car ("I've got someone to drive me") and embarks on a terrifying night- time journey, alone on the highway with the headlamps off. But the next morning his friend laughingly observes: "My car ... it doesn't look like it's moved."

There is something elegantly cold and misogynistic about the narrative's treatment of women who are neither young, slim, nor beautiful: watching a fat woman turn a sharp corner in a stairwell reminds Martin of a cat manoeuvring in its litter tray. Nina, the thin 22-year-old who sleeps with Martin a few times then vanishes, is a standard-issue femme fatale, alternately ardent and aloof. This seems to be a dig at Martin's ludicrous pickiness; later Thomson devotes 100 pages of elegiac first-person narrative to a plain old backwoods beldame.

The book is divided into three wildly unequal sections: the fantasmagorical "Nightlife", "Carving Babies", the creepy reminiscences of Edith Hekmann, Nina's grandmother, and finally "Silver Skin", its title a moving, if oblique, metaphor for Martin's breakthrough into what Visser once promised him: "the development of a new personality, with different capacities, different potential".

Along the way are bizarre episodes which make sly winks at magic realism: the progressively more fantastic tricks performed by his circus pal, Loots; the orgiastic, humping couples which only Martin can see on the second- floor corridor of the Hotel Kosminsky; the titanium plate in his head which broadcasts porn and game-shows. The denouement might be worthy of Ruth Rendell, but until then Thomson's mischievously misleading methods ensure that we keep bumping into the furniture while he creeps ahead in soft-soled shoes.