What is an art gallery? It sounds like a silly question, but in the dark days of the coronavirus pandemic it became less so. During lockdown, all of Scotland's big, state-funded galleries closed their doors. No National Galleries of Scotland in Edinburgh, no Kelvingrove or GoMA in Glasgow. And, of course, all the hundreds of privately run commercial galleries were forced to close too.

In spite of this, however, The Scotsman's two art critics, Duncan Macmillan and Susan Mansfield, were able to keep on reviewing exhibitions hosted by galleries up and down the country as if nothing had happened. Somebody casually leafing through our visual art coverage for 2020 and 2021 might not notice any obvious difference from the years immediately before and after.

How was this possible? Because it turns out that an art gallery isn't simply a physical space – it's also an intellectual construct, a complex tangle of relationships and ideas that exists in between artists and the art-consuming public. And such things are not so easily killed.

Sculpture by Helen Denerley at the Kilmorack Gallery, April 2009 PIC: Roger Cox / National World

The reason we were able to keep on reviewing art shows during the pandemic was because when lockdown began, many galleries – like Tony Davidson's Kilmorack Gallery, housed in a characterful 18th century church near Beauly in Inverness-shire – switched seamlessly from hosting physical exhibitions to showcasing work online. And, for the most part, they did it with an incredible degree of technical sophistication. Yes, of course, seeing a digital reproduction of a work of art online will never be quite the same as seeing it in the flesh, but the experience is now very close. Just take a 3D tour of the Kilmorack Gallery if you don't believe me.

Of course, this pivot to digital from in-person selling didn't happen overnight. The galleries which led the way during lockdown had been working on improving their digital offerings for many years beforehand, and this is a recurring theme in Davidson's illuminating account of more than a quarter of a century of running Kilmorack.

As early as March 2005, on a head-clearing walk beside Loch Affric following a fruitful but bruising experience at a London art fair, Davidson is hit by the epiphany that "the world, the digital continent, has no geography, no London." He resolves to enhance his gallery's digital presence but – intellectually-speaking – to stick to his guns and show "Scottish artists in an international context".

"I don't need London or art fairs," he decides, "just vision."

Confessions of a Highland Art Dealer, by Tony Davidson

When it comes to running a successful art gallery, of course, the "vision" bit is the key to the whole enterprise, and, in a sense, Confessions of a Highland Art Dealer is Davidson's articulation of his vision for Kilmorack, or at least, the story of how that vision has developed over time.

To begin with, his philosophy is bold and simple – first rule: "start at the top and work down"; second rule: "breathe life into something and then feed it." By aiming high, he manages to attract some very notable artists to his new enterprise, notably celebrated Pop artist Gerald Laing and landscape painters Allan MacDonald and James Hawkins, and then – perhaps a more difficult trick to pull off – once he's up and running he manages to keep the momentum going, through economic downturns and subtle-yet-significant shifts in the art market.

The story of a Highland art gallery might not sound all that exciting, but Davidson's book is an unexpected page-turner. Partly this is because his elegant, unpretentious prose flows so effortlessly from one idea to the next, but mainly it's because the narrative that unfolds is so compelling – a tale of perpetual innovation and reinvention; of constantly cultivating existing relationships while also forming new ones. His writing on art and artists is excellent too: he's highly perceptive on the art and also creates some wonderful pen-portraits of the artists. The only real criticism is that the period following 2008 doesn't get anywhere near as much attention as the early years. Perhaps one day we'll get a Confessions Part 2.

Confessions of a Highland Art Dealer, by Tony Davidson, Woodwose Books, 267pp, £8.99. For more on the Kilmorack Gallery, see www.kilmorackgallery.co.uk

Book review: Confessions of a Highland Art Dealer, By Tony Davidson