Imelda Mendes - 'Em' to her children - suffers from a bipolar disorder which flips her state of mind from the outrageously manic to the depths of depression without warning.

In her manic phases she is "a wild animal with flecks of foam at its mouth" raving and raging at the world She is paranoid about "them" - the enemies who are conspiring to harm her and her family - and regularly excoriates her children with the mordant lash of her tongue, often with colourful obscenities thrown in. In her depressive phases, she cocoons herself in her despair, becoming unreachable even to her family, and tries to kill herself from time to time. Yet Em can also be a loving wife and mother to her husband 'the Big Hoom'- nicknamed such because of the noise he makes when he breathes and speaks - and her children, Susan and the unnamed son who is the novel's narrator.

The story begins with Em recounting events in her life to her children when they are visiting her in hospital after her latest failed suicide attempt. The son probes his mother's life story in an attempt to understand her madness, prompting her to recount tales of her childhood and her working life as a teacher and an office worker, her courtship and marriage, and the trials of motherhood which she felt totally unprepared for. Em is a natural storyteller, and from her anecdotes a picture of a charming, rather innocent and completely normal young woman emerges, before the illness takes hold. "After you were born," she tells him, "someone turned on a tap. At first it was only a drip, a black drip, and I felt it as sadness … It's like oil. Like molasses, slow at first. Then one morning I woke up and it was flowing free and fast. I thought I would drown in it."

The son reads his mother's letters and diaries to flesh out the whole story of her life, and the novel develops into a memorable account of one woman's mental torment; but more importantly it also becomes a vivid portrayal of the effects of her mental illness on her family: "Suddenly, your mother steps into a patch of quicksand… Some part of you walks on and some part of you is frozen there, watching the spectacle. You want to stay but you must go."

The agony of wanting to reach out to his mother but being unable to takes its toll. He and his sister are constantly making allowances for her, blaming the madness for her hurtful behaviour. They want to look beyond the illness to the mother they know they cherish and who cherishes them, but sometimes it becomes impossible. Once, after a blisteringly sarcastic tongue-lashing from his mother, the son reacts as any son might to his mother: "I could not remember ever feeling so violated and hurt.

"'Shut up,' I said and I could hear my voice beginning to tremble with tears. 'Shut up, you disgusting bitch.'"

In her future bouts of manic behaviour, Em does not let him forget this, casting it up to him in all sorts of ways ("Can the disgusting bitch make you some tea?") and even signs a demented note to him "The Disgusting Bitch".

The son recounts a particularly harrowing visit to the mental hospital in which he encounters an old lady roaming around reciting her address. She pleads with him to take her there and shows him her discharge papers. He assumes that she has forged them, but when he asks the warden, he is told they are genuine. When he offers to take the old lady home, the warden tells him that her family has gone, leaving no address.

The pitiful desperation of that family situation serves as a control against which to judge Em's family, and the lasting impression we come away with is that the husband and the children's love for the mother, though it does not overcome her illness, helps to make it manageable.

Jerry Pinto's prose is lively and incisive. Though the subject matter is grim, the treatment is not, and there are moments of great humour here as well as moments of tenderness and poignancy.