This might be the most astonishing, the most beautifully written memoir that I have ever read.

Anna Lyndsey was a civil servant when light began to affect her. What began as irritation when she worked in front of a computer screen grew into a condition where she had to live in darkness, in a room completely and utterly blacked out, wrapped in dense, heavy clothing, because even the faintest hint of light – natural or artificial – would cause her agonising pain.

As her sensitivity increased she tried different things – an indoor job as a piano teacher, any number of therapies – but the progress of her condition was inexorable.

And so you should take the title of this book very, very literally.

It really is the story of a girl who lived in the dark.

She skitters backwards and forwards thorough time because, writing about different aspects of her life in the dark, catching different moods and emotions. It’s very effective, and, though sometimes it’s dislocating, maybe that’s the point.

That means that this is a veritable treasure chest of a book:

There is gorgeous literary writing about what it is like to live without light, and about how that changed her perception of so many things.

“I sit in the dark and listen to the storm. I hear the bitter clatter of rain against my walls, and the low book of the wind, a strange unsettling frequency that makes the bones in my skull vibrate.

My ears exult in the glorious accumulating noise, my blood foams with the energy of the storm. The world outside is trying to reach me, roused from its usual indifference. It drags its claws along the bars of my cage. It puts its mouth to my wall, and roars.

My body has learned to sit quietly in my room. It has learned not to scream or sob or writhe. But my spirit swirls lie the wind, surges lie the rain. The wildness outside calls to the wildness within.

‘I hear you,’ I cry out in my mind. ‘I’m here, keep going, don’t stop’

There is advice for how to manage life in the dark. Audiobooks would prove to be a lifeline, but music had to be approached with care because it could stir too many emotions. Word games – for one, or for two when her husband, friends or family were with her – provided both entertainment and mental exercise. And of course there are more basic and more fundamental points: how to find things in the dark; how to keep fit, how to, somehow, keep going.

There are firm words for medics and local governments, caught up in bureaucracy, and lacking the flexibility that is so very necessary for dealing with extraordinary circumstances. The relationships, the support that they might have given came instead from the few others who were loving with similar conditions.

And there are quietly appreciative words for her family and for friends who put themselves out to do whatever they can for her.

“People make me tidy up my psyche, as one might order the magazines on the coffee table before a visitor arrives, and afterwards, for a while, they will stay that way, before entropy reasserts its hold.

People remind me of my true shape, the particular bent of my mind, the curve of my wit; that I have substance, though I move wraithlike among shadows, that the years before the darkness laid down rich sediment which has not been washed away.”

The way that her husband rose to deal with the challenges of her condition, to deal with living a life very different to the one they had planned was wonderful

Above all this is one woman’s testament; it catches her memories, her hopes, her dreams, her fears; it catches the full range of her emotions, from the humour that she finds in many things to the suicidal impulses that she struggles to keep at bay.

Her words feel honest, and her life – extraordinary though it is – feels real. She is wonderfully eloquent, and  her story speaks profoundly about the human condition.

Though there would be periods of remission – periods where she could, after her husband had prepared the house, venture downstairs; periods when she could even step outside the house at dusk – the dark would always pull her back. She would find no answers to questions about what caused her condition or to questions about what the future might hold.

That was frightening, but it also allowed a little glimmer of hope into a blacked-out world.

This is a wonderfully readable book; I found it hard to put down, and I know that it will stay in my head and in my heart.