TEMPTED to follow your dream and open a second-hand bookshop? Don’t do anything before you read Shaun Bythell. Bythell runs The Book Shop in Wigtown. No other shop in Scotland has as many second-hand books as his does: some 100,000 of them, covering almost every conceivable subject. This entertaining and illuminating book, a diary spanning the year to February 2015, sees him reflect on subjects from the raging, unstoppable growth of Amazon to the customers who each day enter his store.

Ah, the customers. Some of them seem pretty decent, like the middle-aged Mr Deacon, whose brisk and concise transactions make him the ideal customer. “He never browses and only ever comes in when he knows exactly what he wants,” Bythell observes.

Would that every customer could be like Mr Deacon. Some people wander into the store, single out a book and say, within earshot of Bythell, that they could get it more cheaply on Amazon. Others bring a book to the counter and try to wheedle a discount on an already modest price.

Bythell has fielded phone calls from irate customers who, it emerged, were talking to quite the wrong bookshop. One Amazon customer makes a thinly veiled threat to write a negative review on the company’s website because he has yet to receive his ordered book. A Welsh woman phones up now and then: she “has the most depressed voice I have ever heard and always asks for 18-century theology”. A regular visitor is William, or Agnes, an octogenarian transgender man/woman from Irvine. Other people traipse in, thinking that their first edition of Harry Potter And The Deathly Hallows is worth a small fortune, only to be told that, well, actually, no fewer than 12 million copies were published.

And then there are the casual visitors, some of whom leave an impression on Bythell for all sorts of unexpected reasons. This is from his diary entry for April 16: “Two very sweet ginger-haired girls ... asked if this was Captain’s shop [Captain being the shop’s cat] … While we were chatting about how fat Captain has become recently, a man in an extremely tight pair of shorts came to the counter and bought a book called The Book of Successful Fireplaces.”

An “extremely haughty” woman, author of an autobiography entitled No, I Am Not Going to the Seesaw, rings up to demand the use of the shop’s mezzanine bed for the duration of the Wigtown Book Festival.

Together, such customers would seem to support a contention (quoted here) by George Orwell, who once worked in a bookshop: “Many of the people who came to us were of the kind who would be a nuisance anywhere but have special opportunities in a bookshop.”

BYTHELL is wryly funny on the subject of Nicky, a (now departed) worker in his shop, “as capable as she is eccentric”, and who rarely, if ever, does his bidding. Her habits include raiding the skip behind a Morrisons supermarket and bringing in all manner of revolting foodstuffs in celebration of what she calls “Foodie Friday”. A Jehovah’s Witness, she likes to discuss evolution, and puts Darwin’s On the Origin of Species in the fiction section; her boss retaliates by placing copies of the Bible (which Nicky argues is history) among the novels.

The National:

Bythell acknowledges that he conforms to the stereotype of the impatient, intolerant, antisocial bookshop owner depicted by Dylan Moran in the TV series Black Books. He’s quick to put customers’ inane remarks into his book or on to the shop’s Facebook page. And now and again there’s a vague whiff of Basil Fawlty about him as his gaze alights upon, say, “a very irritating man with a greasy moustache” or, as he rejects the offer of books from a bearded hipster “primarily because he kept calling me ‘Buddy’.”

Bythell writes with compassion about the melancholy thoughts that are provoked when it comes to sifting through the book collections of the recently deceased. He touches on the joys of finding a genuinely rare item, and is alert to the nuances of small-town life when writing about the place where he was born.

Bythell has run the shop since 2001. Other people might have crumbled under the weight of the necessity of staying in profit; the constant presence of Amazon; the tedious questions; the “unending, exhausting, haggling” customers. Despite it all, he says, he would not change any of it, and good for him. Second-hand bookshops are alive because of people like Shaun Bythell.

The Diary of a Bookseller by Shaun Bythell is published by Profile Books, priced £14.99