No wonder City Books owner Paul Sweetman compares the bookselling process to “a doctor diagnosing a patient”.

His shop is situated in Brunswick Town, which has one of the highest numbers of graduates per head of population in Europe. Inside his Hove miscellany, 20 and 30-something feminists and left-wingers elbow their way through 10,000 titles searching for polemics, while 60 and 70-year-olds pick out high-end literature.

“There is no point giving someone a Booker Prize winner if they enjoy romantic fiction,” he says, referring to some online sellers whose recommendations throw up odd combinations.

“The skill is in identifying what books our customers want to buy. By doing that you end up with a place that is heaven for book browsers.”

Sweetman’s knowledge and stock selection – “interesting books published by independent publishers” – is the reason why, 25 years after turning the former greengrocer’s into a two-floor readers’ haven, his profit has increased every year but one.

Yet things have not been straightforward. The day City Books opened someone came in to tell Sweetman it wouldn’t last three months because businesses in Brunswick Town never do.

“That was encouraging,” he jokes, “after only an hour of opening.”

Along with partner Inge, Paul hung on through the 1980s and slowly built a brand. However, when Borders opened in Churchill Square in 1998, things looked ominous.

The American chain arrived as the net book agreement – the pact to sell books at a universal cover price – was disbanded. Borders doubled book-selling space in the city and with its buying power, sought to undercut competitors. Waterstones reacted by opening another floor. The death knell seemed to arrive for the city’s independent booksellers.

The Sweetmans kept calm.

“We’ve always been very positive people and, rather than panicking, we started to do outside events, sell books at festivals, organise our own events.

“We took a hit that year. But we built up business from there and we’ve seen them off.”

Thanks to the old-fashioned, pile-’em high approach, the stacks of signed copies on sale and creative promotions – free recipe books with cookbooks, for example – customers travel from far and wide.

Only last week a lady bussed in from Rye after reading about the shop in a Peter James novel.

Sweetman says Peter Wright’s Spycatcher is atop the shop’s all-time bestseller list. The former spy’s memoir was banned in England because he’d signed an Official Secrets Act. City Books avoided court by selling an Australian edition.

Stupid White Men by Michael Moore was another big shifter.

“It was perfect for our customers: eccentric, a little bit left of centre, very entertaining, written by an intelligent man of the moment.”

Moore signed 1,000 copies after an outside event at the Duke Of York’s Picturehouse. A great occasion says Sweetman, but his favourite was when Will Self interviewed Nick Cave.

“It was the hottest ticket in town. We had enquires from all over the world. Some people even came from Japan.”

To celebrate the 25th anniversary, ten events have been organised. The quality is typically high.

Former Chancellor of the Exchequer Alastair Darling opens the festival tomorrow with a talk about 1,000 days in Number 11. It’s a real coup, says Sweetman, because, “It’s not one of those memoirs that are trying to rewrite history or put a gloss on things. It’s brutally honest.”

At the weekend, New Encyclopaedia Of Brighton author Rose Collins will share anecdotes on two Walkie Talkie Tours around Brunswick Town. Lewes poet John Agardis is launching Goldilocks On CCTV at the birthday festival on Saturday, while, later in the day, Erin Pizzey and Catherine Hakim will discuss their contrasting ideas about what it is to be a woman.

Sweetman seems most excited about the Brighton-based children’s author Emily Gravett giving a rare talk about her new book Again!, which follows a stubborn dragon who wants the same book read over and over. Perhaps that’s because the booking process seems to reflect everything that makes the shop so special.

“She wasn’t going to do anything to publicise this book but she made an exception for us. Maybe that’s because her partner Mik is my plumber.”

* Various times and prices, for tickets call City Books on 01273 725306

* Read an interview with Emily Gravett ahead of her talk at The Old Market in The Magazine, free with The Argus on Saturday