The Spare Room, by Helen Garner

How competent I was! I would get a reputation for competence," Helen thinks smugly. She little guesses what is coming to inhabit the spare room of her Melbourne house, when she prepares to receive her terminally ill friend for three weeks. Nicola will have alternative "treatment" in the form of Vitamin C injections and cabbage juice from the predatory crooks of the Theodore Institute. She denies that her cancer will kill her and refuses morphine.

The conflict between terminal lies and blazing truth that develops exemplifies what one might call the domestic sublime. The Spare Room is a brief epic witnessing the clash of titanic wills, imperious personalities, in intimate space. Life and death, host and guest, engage in a bitter, paroxysmic agon, transgressing taboos. Helen's house becomes a force-field of grief, trauma, rage. Yet theirs is a friendship that goes back to their bohemian youth, tender and easy and proven.

In Australia, Helen Garner has a controversial reputation for writing fiction as if it were memoir. This compulsively readable, searing novel narrates the author's own nursing of a close friend through terminal cancer. Author and narrator are called Helen. So is this a fictionalised memoir? Not really. It's a fiction about truth; about witnessing to truth – and, disturbingly, about enforcing it upon the dying. A hymn to friendship tested to its limits, the novel is also a manifesto and a confession.

This is the best book I have read for years. Beautifully written, The Spare Room is terse and pacy. Every taut sentence rings with painful purity and attack. The end is further telescoped, in a brilliant coda. What Nicola brings into Helen's spare room is anathematised as "the sick air of falsehood". Garner builds the spaces and objects of the house thick with sensuous detail, breathed on by irony, trauma and Nicola – and by Helen's towering fear.

Half a banana is "abandoned in its loose, spotty skin"; a blood-red nasturtium blooms; broad beans stand outside the limits of the threatened house, "in hopeful rows". But as Nicola beats off truth, a storm gathers in Helen: "something violent sizzled in me". Tender moments – lying spoonwise with the sweating, pain-crazed woman, watching TV together – give way to Helen's vicious assault on Nicola's coping strategy: "Get that grin off your face. Get it off, or I'll wipe it off for you." The novel validates Helen's behaviour. When Nicola's resistance is broken and she admits "Death's at the end of this", sanity and friendship are restored.

But wait a minute. Has Nicola no right to die in her own way? Is a three-week nursing term so long? Helen apprehends it as a lifetime. Nicola, a splendidly realised character, in her grandeur, pathos and magnanimity, is not the novel's centre. It's Helen's suffering to which we are compelled. How deeply the narrator needs the blessing conferred by sister Lucy, wearing a motor-cycle helmet: "May the Lord ... make his face to shine upon you."

For a subtler and perhaps hardly acknowledged pathology underlies the attack on Nicola's denial and adds to the novel's riveting complexity. Isn't Helen herself in denial? If death is democratic, so is self-deception: when the dying come knocking on our doors, they are messengers and Doppelgängers. In the final pages, washing Nicola's bottom, surrounded by other, more truly competent and merciful friends, Helen acknowledges, tardily and in a subordinate clause, that "some day someone will have to wash mine".

Stevie Davies's latest novel is 'The Eyrie' (Phoenix)

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