Do not be beguiled by the charming book jacket with its vase of flowers, or the tulip-patterned end-papers. Helen Garner's new novel - the first for 16 years from this gritty Australian writer - is not a homely comedy of manners but a matter of life and death.

It begins domestically enough with the narrator, Helen, a writer in her mid-sixties, making up the spare room of the title with considerately chosen bed linen for her cancer-stricken friend Nicola, who is coming to stay with her in Melbourne, where she will attend an alternative-therapy clinic. As it turns out, the clean sheets have to be changed throughout the night, since Nicola's treatment results in shuddering sweats as well as agonising pain, dismissed by Nicola as a sign that the cancer is on its way out.

Helen, who as well as sharing her creator's name and profession, possesses the same unflinching candour, needs to live as truthfully as her friend needs to live the lie that she will get better. With a permanent and ghastly smile “plastered across her face like latex”, and a forced flightiness - her conversation is sprinkled with “darling” and “divine” - Nicola's “tremendous performance of being alive” makes Helen feel that she is breathing “the sick air of falsehood”. While colluding in these attempts to deny death, Helen knows that her chicanery “injects poison into friendship, and makes a mockery of love”. But Nicola insists on practising the tyranny of the terminally ill, a tyranny it would be heartless to defy.

Dying is not Nicola's only problem. She has always been a free spirit, the courageous survivor of childhood rape, drugs and a nervous collapse; until her illness she has dashingly lived by herself in a remote hillside shack beyond Sydney's beaches. Belonging to nobody, she turns friends such as Helen into reluctant nurses. Employing real nurses would be out of the question, since their presence would suggest she was going to die. When Helen, broken by weariness and fright, can't cope any longer with Nicola's demands, Nicola says, “I have dozens of darling old school friends who live in Melbourne. They'll take me into their homes with all their hearts.” Such is her necessary self-delusion that she still sees herself as the irresistible companion she used to be. And this is why she plays down the pain forced on her by the clinic: “It does knock me around somewhat ... And I sometimes come home a wee bit under the weather.” It is her sympathy with Nicola's aloneness that keeps Helen washing sheets and escorting her to the clinic that Helen knows is just an expensive con run by an elusive charlatan. Helen herself, long divorced and living next door to her married daughter and grandchildren, is enviably rooted; she will never have to rely on the kindness of almost-strangers.

In all this heartache, jokes keep breaking through. Nicola's painkilling tablets are called Digesic. “Di-gesic”, Helen suggests, “is so you won't die.” There are sniggery discussions on whether coffee enemas require organic beans or whether instant will do. As the two women embark on a bumpy seesaw ride of brutal showdown followed by abashed acceptance until the inevitable and piteous end, you begin to understand what it is to belong, and not belong. In its bleak and highly comic storytelling, in spite, or perhaps, because of its subject matter, The Spare Room could be called a comedy of manners, in that its concern is how people behave towards each other and the repercussions of that behaviour. Its embattled characters are so real that by the last page you feel not just that you have read a magnificent novel but that you have experienced life itself.

The Spare Room by Helen Garner
Canongate £12.99 pp195 Buy the book from Books First £11.69 including free delivery

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