There aren't many men as obsessed with shopping as Paco Underhill. Whether in Moscow or Mexico City, he will be found lurking in malls and supermarkets, mapping shop layouts and analysing consumers' behaviour. For 25 years, Underhill's "retail anthropology" has informed the Aspreys and the Wal-Marts - insights he shares in bestsellers such as Why We Buy: The Science of Shopping. This year, however, a particular trend has preoccupied him in his travels. Underhill calls it "pop-up" retailing.

Without much warning, a store chain or fashion label will open a shop intended to close after a week, a month or a year. It will sell limited-edition sneakers, test-market unreleased gadgets, reinvent a whisky brand as a hairdressing salon - yet however profitably or successfully, the store will disappear just as suddenly as it popped up. "Think of it as theatrical retailing," Underhill explains. "The line between commerce and fine art has suddenly become really fuzzy. These stores are there to generate buzz. They play the media in a way that most merchants can't."

Fashion brands have been especially keen on pop-up stores in recent months. Camper currently has a temporary shoe shop in Notting Hill; elsewhere in London, Kangol ran a Brick Lane store throughout August that sold bags and sunglasses while DJs and "graffiti artists" performed. In Germany, MTV is using short-term stores to sell goods by adidas, Levi's and Sony Ericsson. At the Cologne store for a week in October, you could buy £350 pairs of limited-edition Levi's dipped in gold leaf, and mobile phones unavailable elsewhere. Flyers and stickers brought in the trendsetters, transforming a mere shop into an event.

"Pop-up stores recognise one of the sad realities of fashion retailing - that you're only hot for so long," Underhill says. Consumers get bored quickly. "We're craving something different. If you walk into a store with the expectation that it's got six months or a week to live, you approach it with a completely different set of values."

Non-fashion brands are also catching on. For a week in August, a cat-food company opened the Meow Mix Café on Fifth Avenue in New York serving food and toys "to cats and the humans who think they own them". A little further downtown, Crown Royal, a whisky, launched a barbershop offering free haircuts for a month.

As a marketing tool, this can prove a remarkably cost-effective means of promotion. "These stores are also a triumph of creativity over money spent on fixtures," Underhill says. Comme des Garçons, which is opening a series of year-long "guerrilla stores" from Barcelona to Singapore, fitted out its Berlin store for just £1,300. The former bookshop still displays signs left by the previous owner, and the clothes are hung from exposed water pipes. Rent is just £360 a month, but the clothes and perfumes retain their high-end prices.

Underhill does not see the novelty fading quite yet - growing media buzz makes pop-up retail a smart investment, he says, and electronics firms are likely to be next at the party. "Although it really is just a curious rewriting of one of retailing's most ancient principles," he reflects. "Is it that different from the travelling pedlar who hawked his wares warning that he wouldn't be there tomorrow?"

david.rowan@thetimes.co.uk