The invisible man marries the Snow Queen

The Heart of an iceberg is deepest blue, at its most intense at sea level "where the ice is oldest and so compacted that all the air has been forced out". This strange and brilliant book recounts Jenny Diski's journey to Antarctica last year, intercut with another journey into her own heart and soul, an examination of her childhood and her relations with her parents, a father who died in April 1966, a mother who two days later ran screaming out of her daughter's life for ever.

Just as Diski's visit to the bottom of the monstrous world is not a pilgrimage, rather "a hopeful voyage in to whiteness", so she embarks on her inner journey without illusions. She does not seek solace or even an understanding of the forces which wrecked her parents' marriage and instilled in her a longing for oblivion so intense that at 14 she overdosed on her mother's Nembutal and now perpetuates her urge for "whiteout" in her bedroom, in her flat, in her sudden compulsion to reach Antarctica.

Her satisfaction in the end is to find that her recollection is truthful, that her mother, mad and sad rather than bad, was the impossible creature whom she herself had of necessity excluded from her life well before her father's death, and thereafter tried to forget. She might be alive, she might be dead. Diski did not want to know. She felt neither anger nor affection. But even before she voyaged to Antarctica, her own 18-year- old daughter was discovering the bare facts of her grandmother's latter years; with reluctance Diski found herself looking in to the past, questioning elderly ladies who had once been neighbours, revisiting the block of flats where she spent 11 years of childhood; so she shored herself up against the outcome, probing the nature of memory.

Once there had been a small loved child called Jennifer. Her mother took her skating every day: "You could skate before you could walk." She was to be a star and her mother would share her glory. Both parents were children of Jewish immigrants; their daughter was to have the best clothes, the best education; she would achieve. By the time Jennifer was four the money had gone and the quarrelling had begun. Here is an extraordinary portrait of a solitary child determined to survive; "portrait" is the necessary word for Diski tells us "Any event occurring to Jennifer always includes Jennifer in the frame. The image is not from her eyes ... but seen from the outside, from some eyes beyond the frame."

Jennifer sits on her father's knee: "What the hell I was doing there (if that actual moment ever existed and is not just a representation of a general memory), standing at one side, at a little distance from the armchair the two of them are sitting in, no more substantial than a pair of observing and possibly ironic eyes, I cannot say. Jennifer was frightened of ghosts. Perhaps she had every right to be."

At weekends Jennifer and her father wandered blissfully round London, going to museums and cinemas and Chinese restaurants. At home her mother waited, angry and excluded. Later weekends were spent visiting her in a mental hospital, re-creating that early merriment on their long walks through the suburbs by knocking on doors so that Jennifer could "use the bathroom. It became a game, a kind of roulette ... Those brief visits belonged to the realm of our earlier museum wanderings; the house and people, the exhibits; our meeting people and seeing how they lived, like the stories my father used to make up about the things in glass cases. They were adventures in to unknown worlds, people whose houses, whose lives looked to me so solid and stable."

Until her books were taken by the bailiffs Jennifer read, played with other children in the block and ranged in total freedom about her domain, the limitless corridors, stairs, fire-escapes and surrounding pavements of Paramount Court. "Even now I can't imagine any suburban or country childhood that would have provided me with so much."

But within the flat, listening to nocturnal warfare, she repeated her prayers for peace a hundred times over, a hundred times tracing a star of David on her chest. She became nervous, elusive and wary of what each parent called the Truth. Her mother was hostile and critical, her father erratic; when she was 11 he left for good. Eviction followed, then years of constant moving, expulsion from school, passing back and forth between parents, Nembutal and mental hospitals. The mother of a school friend offered her a home, her father died and her mother disappeared. No one tried to find her.

There is not an ounce of self-pity in Diski's bleak account, and little warmth either. Images of ice recur, ice that is slippery, treacherous, cracking; a skating rink which promises infinity but brings the skater round and round in ever-repeating circles. In Antarctica Diski finds a Utopia, a no-place of floating Halcyon icebergs, constantly changing, melting, reforming; yet a place which "would also remain essentially the same, its elements nearly rejigged ... Nothing there stays the same but nothing changes."

Such paradoxes abound in a book of dazzling variety, which weaves disquisitions on indolence, truth, inconsistency, ambiguousness, the elephant seal, Shackleton, boredom, and over and again memory, into a sparse narrative, caustic observation and vivid description of the natural world. While Diski's writing is laconic, her images are haunting; her honesty transcends pain. The same honesty turns her away from the dream landscape of the ice world to a practical, perfect place, her cabin on the ship. Here there are white walls and white sheets. Here she may watch the snow falling silently from a heavy sky on to the sea.