Nan Shepherd was a Scottish writer who published The Living Mountain in 1977, near the end of her life, after letting the manuscript sit in a drawer for decades. In my opinion, it's an understated masterpiece of landscape and mountain writing – and one of the best books ever written about the Cairngorms. I am not alone in this view - a new Scottish banknote featuring her portrait is a recognition of Shepherd's significance.

Shepherd spent countless hours tramping through these mountains. Thanks to this long association she gained an intimate knowledge of the landscape, but hers is a unique perspective. For Shepherd, a mountain is not merely a collection of surface features – it's the whole thing, from deep within the bedrock to high up in the sky, and back and forth through time as well.

She wrote most of this book in the 1940s, just before a time of profound change in this part of Scotland. She knew the Cairngorms before the expansion of Aviemore and the development of the ski centres, when a few crofters still maintained a way of life largely unchanged for many decades.

In a quiet yet incredibly profound way, Shepherd documents her experience of the Cairngorms and reveals much of their unseen side to the reader. The writing is luminous – that's the only way I can describe it. I first read The Living Mountain when I was discovering the Cairngorms for the first time. It shaped my experience of these hills.

Most of my mountain reading up until that point had been quite goal-oriented: climbers seeking out first ascents and having epics along the way. But there's nothing like that in The Living Mountain. It allows the mountains themselves to be the characters, freed from human comparisons, motives or ambitions. In a genre where many titles seem to be all about doing, this one is about seeing, sensing, being. It's landscape writing at its very finest.

In his intro to a recently published reprint Robert Macfarlane, author of Mountains of the Mind and The Wild Places, said this about it:

"The Living Mountain is a difficult work to describe. A celebratory prose-poem? A geo-poetic quest? A philosophical inquiry into the nature of knowledge? None of these quite fits, though it is all of them in part. Its prose is weathered in both senses: filled with different kinds of climate, but also the result of decades of contact with "the elementals". It is about the Cairngorms in the same way that Ulysses is about Dublin, or Mrs Dalloway is about London – which is to say, it is attentive to the specifics of its chosen landscape, but also passionately metaphysical."

It is hard to disagree.