Helen Stevenson’s daughter Clara has cystic fibrosis. Love Like Salt is an account of living with the disease, but it is much else besides. Stevenson calls it a memoir, because it is an intensely personal version of events. It is also a scrapbook, a commonplace book, a series of meditations, an exercise in self-scrutiny. It is emphatically not a medical handbook.

Stevenson is a writer, translator and musician; her husband Nico, ‘the kindest man on earth’, is a retired academic and translator of poetry. The book is structured like a piece of music. I’m too ignorant to give you the correct terminology, but there are three movements, and all the shorter passages branch away from, and then return to, the central theme.

The effect is cumulative. To take just the first few pages: a brief preface describing cystic fibrosis is followed by the folk tale from which the book gets its title; a sketch by Clara (now in her teens) of a girl peering round a door; a quotation from Balzac comparing the raising of a child to the creation of a work of art; a passage in which Stevenson sets the scene for the French village where most of the ‘action’ takes place; a quotation from Anna Akhmatova about receiving bad news: ‘And the stone word fell/ On my still-living breast.’ After all this, the narrative itself begins, the story of the tiny baby ‘failing to thrive’, so fragile that her mother ‘thought of her as a candle, cupping my hand around her’.

Clara and her younger sister Verity were born in London, but Stevenson was in pursuit of ‘the idea of France’. As a reader and writer, she sought that intangible feeling that literature provides — ‘it was the lost domain before I ever found it’. Perhaps she could write a script for family life that could somehow accommodate or neutralise the huge fact of Clara’s illness. The attempt ultimately fails: ‘I had dreamed of a house, a life, a story, but I had chosen wrongly…We are often looking for things that do not really exist.’

At exactly the time of Clara’s birth, Stevenson’s mother began to show the signs of the dementia that will soon kill her. The way Stevenson interweaves the story of her mother’s decline with that of her own growing understanding of what it means to care for Clara is exquisite. At the heart of the book is the story of her involvement in a performance of Pergolesi’s Stabat Mater:

It is a work about grief, female grief, the collective experience of aloneness, and most particularly the grief of a mother. Stabat: she stood, was standing, the imperfect tense which permits no end, she stood and is still standing, rooted to the spot, being present to the pain of the beloved child.

Life and art are inseparable. While the musicians rehearse, the children play beanbag sledging on the slippery floor.

As the children approach adolescence, Clara’s condition repels and unsettles the very people who once seemed entranced by her. At school, her medicines are tipped onto the floor. Parents refuse to let their children play with her, as if she were accursed. Stevenson suspects that she is partly to blame for the way the French idyll turns sour. Stress reduces her to a ‘state of alienation and rage’ in which she turns relatively trivial slights and misunderstandings into ‘a plot’. But there is no excusing the dinner lady who refuses to let Clara take the enzymes without which she cannot digest food. The family return to England, to rural Somerset and a Quaker school which seems to offer both girls a chance to be true to themselves.

‘Let your life speak,’ the Quakers say, and this is exactly what Helen Stevenson has tried to do. The result is an intelligent, complex, deeply affecting book about love, motherhood, ghosts, music, poetry, sickness, health, religion, magical thinking, time, place, and the things that get lost in translation. At the same time, it’s highly readable. As Verity says, ‘It’s just a book of stories that happen to be about us.’