BOOKS / Thunder, fire and burbling birds: Jan Morris on a brilliant account of a woman on the loose in the Australian outback: Daisy Bates in the Desert - Julia Blackburn: Secker, pounds 16.99

Julia Blackburn's brilliant new book, Daisy Bates in the Desert (Secker, pounds 16.99) is in every way a mystery. It concerns a strange woman, Mrs Daisy Bates, living out her life among a recondite people, the Australian Aborigines, in one of the world's most eerie places, the Nullarbor Plain. More than that, it is a haunting puzzle in itself, an imaginative weaving of facts, conjectures, evocations and emotions that left me feeling rather as I do when I awake from a particularly tantalising dream - the sort one mulls over, amazed, baffled and enchanted, until it is time to get up.

Now that biography has mercifully replaced travel writing as the genre of the day, we may expect virtuoso workings of the form. Peter Ackroyd introduced the idea of dialogues with his biographee. Julia Blackburn goes a stage further by more or less metamorphising into her subject, so that Daisy Bates becomes not only the matter of this work, but in an ectoplasmic way its narrator too. Sometimes we are inspecting her from the outside, sometimes we inhabit her spirit looking out, so that the portrait is many-layered, misty, suggestive, rather like a picture that needs cleaning.

Nobody could suit such a technique better than Daisy Bates, nee O'Dwyer, who virtually invented herself anyway. She was a celebrated figure of the Australia between the wars, having devoted herself to the study and welfare of the Aboriginal peoples long before such attitudes became politically essential. Living for decades alone in the Nullarbor with a shifting and wavering flock of primitives, she became to some a figure of mockery and contumely, to others an all-but-saintly legend - 'Kabbarli', the Great White Grandmother, 'one of the most romantic figures in the British Empire', as Arthur Mee, the editor of the Children's Newspaper, described her in 1938. Her life among the Aborigines was perfectly true and genuinely heroic, although her studies were derided by anthropologists and in later years she was accused of a meddling matriarchism. However, as if her circumstances in the outback were not arcane enough already, she created another existence for herself which was entirely fictional.

She dreamed up grand origins in Ireland (in fact she seems to have been brought up at a Dublin orphanage), quoted aristocratic patrons and connections, claimed to have met Queen Victoria and fitted herself out with a largely spurious curriculum vitae. To cap it all, and to seal the union of truth and fantasy, she really was bigamously if briefly married at once to a horse- trainer named Jack Bates and to the notorious 'Breaker' Morant, who was executed for murder at Cape Town during the Boer War.

Dismissing the memory of 'Breaker', heedlessly casting off Mr Bates and their son Arnold, this peculiar lady withdrew into the Never-Never: and there Blackburn, her perfect memorialist, catches up with her 40 years after her death. The book's blurb makes too much, I think, of Daisy Bates' mendacity. It was harmless and unimportant, and its real part in this work of art is to release Blackburn herself from any restraints upon the fancy. Fact and fiction, dream and reality - she has Daisy Bates' own sanction to disregard the boundaries between them, and to present the story as one long wistful compassionate drift of mind and memory.

Some readers will want to know the hard truth, and for them a bibliography is provided. The book itself skims over the debatable past and tells us nothing about Daisy Bates' posthumous reputation (From Sainthood to Scandal is one of the titles in that bibliography). It is what it says it is: a book about a woman in a desert. All the sensations of the Nullarbor are almost creepily evoked - the heat and the red earth, the burbling birds and the smell of the wood fires, the thunder of the East-West express storming out of nowhere. We feel all but physically closeted within Daisy Bates' miserable tent, cluttered up with her meticiously maintained wardrobe of ladylike dresses, her mountains of notes and diaries, her trunks full of observations anthropological, zoological, botanical or eccentrically philosophic.

All around her tight-laced little figure, five foot two but frightfully regal, there swarm and squat the Aboriginals. They are the point of it all. 'My people', Daisy Bates called them in her grande dame way, but she never really felt herself one of them, Her purpose was, she once wrote, 'to make their passing easier and to keep the dreaded half-caste menace from our great continent', and willing though she was to share their victuals, bury their dead and tend their sicknesses, she never gave up her crepe de chine underwear, her high-buttoned boots or her status as a Commander of the Order of the British Empire.

Sometimes the Aboriginals disappear for pages, even chapters at a time, but their fragile shambled presence pervades the whole book, just as they came to displace the patricians of old Ireland, even Oueen Victoria herself, in Mrs Bates' innermost imaginings.

Julia Blackburn evokes them without sentimentality, without any Songlines gobbledy-gook, in a gentle soft-focus that is entirely convincing. I feel I shall for ever be able to see them, King Billy, Fanny Balbuk, poor mad Dowie like Lear in the wind - all blurred but unforgettable, emerging like wild creatures out of the deep desert, begging for cigarettes beside the track as the train goes by for Adelaide, hanging about Kabbarli's camping-site while the old lady does her morning skipping exercises, feeds spiders to an injured lizard, or boils up a bowl of porridge for the lot of them.

It is an enchanting book; like one of those dreams.

I am Daisy Bates in the desert, stretched out on the floor of my tent, surrounded by the intense heat and dryness that has not let go for months, or is it years. It is much too hot to move. I lie on my back, naked and wrapped in a white sheet, my eyes closed, my mouth slightly open. I suppose I must look like a corpse waiting patiently for its coffin. I lie here still as a stone and my thoughts race in all directions: backwards and forwards as if there was no past and no present time, just a single exploding moment in which everything else is contained. As a child I learnt how to amuse myself with thought. I could be trapped in a dark room and still I was free to go wherever I chose to go. I could stare into the darkness and watch as intricate images floated to the surface, as bright and vivid as sea creatures in the moment when they have been pulled out of the water. Sometimes I was frightened by the intensity of my own imagination but I have learnt to get used to it now, to tame it in a way. As soon as I began to talk to the people here I realised that they have a similar ability, but more powerfully developed . . .

(Photograph omitted)