He turned his secondhand bookshop and its annoying clientele into a hit book and now Scottish author Shaun Bythell is heading from Wigtown to WORD Christchurch.

Shaun Bythell wanders into the cool of his shop looking like a man whose natural shagginess is being made even shaggier by the heatwave outside. It’s a cloudless, high-20s Thursday in his hometown of Wigtown, a village in Scotland’s pretty, uncrowded and often-forgotten south-west.

The afternoon sun is streaming through the back windows of The Book Shop, a labyrinth of 100,000 pre-owned volumes. There’s a particular threat of fading on the astronomy shelves, which is only fitting.

A slightly harried Bythell asks the Listener to have a look around while he deals with some urgent matters. He’s just been doing a house conversion of an old pub down the road, he explains later, and he’s organising a golden wedding anniversary celebration for his parents, who live nearby.

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“Having a look around” has its risks. Such as getting caught in a book avalanche in the railway section. It’s impressively stocked, especially considering the trains stopped running to Wigtown in 1964. Quite a few things have stopped running here since. The dairy factory shut in 1989; the local distillery has closed and re-opened multiple times. It’s now a boutique operation.

So is Wigtown itself. The hamlet of one thousand or so lives on as “Scotland’s National Book Town” with its many book shops and its annual writers’ festival. There is a shop you can stay in and run as you see fit; it’s available as a holiday rental and it’s booked out years ahead.

The Book Shop, which Bythell bought in 2001, at age 30, proclaims itself Scotland’s biggest second-hand book emporium. Near the front counter, though, there are some rarities – new titles. There’s a small stack of Bythell’s own The Diary of a Bookseller, his funny, pithy, grumpy poignant memoir of a year in the shop’s life and its occasionally annoying clientele. It was published last year and has gone quietly global.

Also for sale are copies of Three Things You Need to Know About Rockets by Jessica Fox. Fox is Bythell’s American former girlfriend. While working as a Nasa media consultant, she ventured to Wigtown during her holidays, stayed on and wrote the 2013 book about it. She inspired Bythell to have a crack at his own. He kept the diary, sent it to an agent he had met at the festival, she found a publisher and he fleshed it out.

Now, the rights to his and Fox’s books have been sold to turn both into one film or television series.

But right now he’s dealing with life as an in-demand author. He’s also become an accidental anti-Amazon champion, having fumed against the online retail giant throughout the Diary’s pages. A Kindle he blasted with a shotgun is displayed as a trophy on a shop wall, though that hasn’t stopped some customers checking prices online while browsing the shelves.

These days, Bythell, a man described by one of his staff in his book as ‘‘the big ginger conundrum’’, juggles managing the shop between promotional duties for his book and his publisher’s demands for further instalments.

Bythell finally sits down to talk in the upstairs kitchen of the house, which, in the storeys above the clutter of the shop, reveals its former Georgian splendour and a wide-horizon view out across Wigtown Bay to the Irish Sea.

Though he was born locally where his parents farmed, Bythell sounds more English than Scottish. That’s a product, he says, of his Irish mother, English father, and his time at boarding school from the age of seven. His years away, his time at university and an early post-graduate job as a television documentary researcher in Bristol just made him want to come back to stay.

“It just has that sense of home for me,” he says. “And I think, partly because I went away to boarding school when I was seven, I really felt such a keen yearning to be back here. I think that’s never gone; this feels like the place I’m comfortable.”

The Diary is funny in its descriptions of books and those who treasure them in the way that Nick Hornby’s High Fidelity was funny about records and the people who sell them, though Bythell was inspired more by George Orwell’s essay Bookshop Memories (more on which later) and Jen Campbell’s Weird Things Customers Say in Bookshops.

His book wreaks droll revenge on patrons who considered the customer-is-always-right adage an excuse for arrogance and ignorance. He’s lost a few regulars because of it. “Bumbag Dave”, for one, hasn’t returned.

“He was a good customer, actually. I quite liked him … he wasn’t pleased at the way he was portrayed. I could have maybe been a bit kinder to him.”

Bythell and former staffer Nicky, a supplier of much of the book’s character-based comedy, had a falling-out over something that happened after the Diary’s year ended. But she’ll still be in the next book.

The memoir does have episodes that aren’t there for laughs. His van trips to assess the collections of deceased estates offer melancholy pictures of how some people’s lives may be defined by the books they leave behind.

A few days earlier, he says, he was in Yorkshire dealing with the widow of a former book dealer who had been a regular caller at the shop.

“I didn’t even know he had died. Sometimes you get your regular customers and you don’t notice when they stop coming in.

“If you live in a rural community you can’t self-select your social group; you socialise with everyone, and bang, they’re not there. It’s definitely something that makes you much more conscious of your own mortality.”

On the lighter side, the memoir also touches on the joys of fishing with his father and going sailing and mountain-biking with his mates. It’s proven quite an advertisement for the area, which isn’t a well-trodden part of Scotland’s tourist trail.