Editor-At-Large: Janet Street-Porter

This year's Christmas present for style gurus has just arrived. Weighing in at several kilos, it's a thick, black and gold bound volume with a gold escalator engraved on the front. Edited by the world's most fashionable architect, Rem Koolhaas, this is the latest in a series of coffee-table books about the built environment that you don't necessarily read, you just place in a prominent position.

A few years ago Koolhaas came up with this volume's forerunner, entitled S,M,L,XL. My coffee table nearly sank under the weight. Wallpaper* readers rushed to purchase this virtually incomprehensible manifesto about the way to live. Now Koolhaas and his team of editors have devoted an entire volume to shopping, arguably the most popular religion of the 21st century. Starting with a history of shopping malls, and citing the Great Exhibition of 1851 with Paxton's Crystal Palace as a role model for the future, this book is both exhilarating and deeply depressing.

Koolhaas is the latest architectural genius to fall under the spell of the retail trade. A philosopher, writer and theorist, he attended my old college, the Architectural Association. When I met him last week he was six foot plus of dynamic nervous energy with the attention span of a gnat. Dressed from head to foot in navy blue, he looked like a frenetic pipe cleaner.

Koolhaas has overtaken M. Philippe Starck as the architect everyone feels comfortable with – from hotelier Ian Schrager to Birmingham City Council, for which he is designing a library. Dutch born, he's based in Rotterdam and is both prolific and unsnobby, working on everything from a concert hall in Oporto to the latest branch of the Guggenheim Museum, which has just opened as part of a hotel in Las Vegas.

Once, young architects cut their teeth on small shops, then moved on to bigger, more worthy projects such as museums and public buildings. Koolhaas has turned the convention on its head. He's designed the Dutch embassy in Berlin and a railway terminal in Lille, but his latest project is to create three boutiques for Prada in New York, Los Angeles and San Francisco. Far from being a chain, it's envisaged that every shop will be completely different, reflecting a theme to do with the city it is based in.

Of course, this is a brilliant wheeze on the part of the canny Miuccia Prada. Having set up an art foundation complete with gallery in Milan, and funded the Italian America's Cup yacht team, she and her husband can now use Koolhaas to elevate the Prada brand from just another luxe line to a series of style temples, worthy of a pilgrimage even if you're not interested in the clothes. By aligning itself with Koolhaas, Prada tells us a lot about how fashion designers will seize on anything to sell us their wares – in this case clompy shoes and perfectly plain skirts and blouses. The heady combination of high architecture and incredibly expensive clothing will create the first of a series of 21st-century temples: miniature cathedrals where devotees can wave gold credit cards about as they worship.

The Harvard Design School Guide to Shopping (edited by Koolhaas) asks if shopping is the new sex. It shows, via a series of clever graphics and charts, how mall culture has permeated every aspect of our lives, from out of town sprawls to railway stations to theme parks to museums to airports. The mall concept is everywhere you look, suffocating in its blandness, uniformity, its non-threatening completeness, its artificial climates. Malls have killed city centres and now they are like a fungus polluting cultural institutions and underground stations. You can't walk a hundred yards in a large city without encountering a version of the shopping mall. We can't worship, eat, look at art or go to a hospital without incorporating shopping into the experience. Furthermore, shoppers feel most comfortable being effortlessly moved from one zone to another by that key component of the shopping mall, the escalator – hence the gold one on the book's jacket.

The irony of all this theory, no matter how accurate it might be, is that people like Rem and Mrs Prada wouldn't be seen dead in a shopping mall. Neither will the fashionistas willing to shell out £30 for this entertaining volume. Mall shopping is naff as it's so readily available. Do you know anyone who would admit to spending a morning at Newcastle's Metro Centre or Brent Cross or Bluewater in the South-east?

Koolhaas's team allude to the growth of "brand zones", where high-visibility brands cluster together in areas such as Bond Street or Brompton Cross. You only enter these zones with the right credit cards and the ability to deal with snooty shop assistants and ludicrous prices. Shopping has polarised, and practicality and price are simply not the issues. At the very point when shopping became easy, practical and convenient, with parking, on-line ordering and endless variety on offer, what do we desire? One-off shops where we can buy a Gucci dog bowl or a Dior diary.

Of course, these are massive brands, really no different to Asda or Karen Millen. But the new architect-designed temples disguise all that brilliantly, by endowing retail goods with heavyweight philosophy and visionary concepts. It's not even necessary to have much on display. As with the medieval religious relics visited by million of pilgrims, less is more. One pair of Louis Vuitton shoes cunningly presented can take on the cultural weight of the Turin Shroud. Wal-Mart's sales are larger than the gross domestic product of three-quarters of the world's economies. But malls are in crisis. The average time people spent in them dropped by half during the 1980s. Surveys found that people planned to use malls less in the future.

On-line shopping has ended its honeymoon period, too, with the revelation that we are still addicted to shopping, but we want it to be validated by being a weird, one-off, intensively designed experience. Department stores have to endlessly reinvent themselves. So where does that leave the smart Mr Koolhaas? In a couple of weeks his first Prada Store opens in New York, part of the downtown Guggenheim in SoHo. So you can shuffle reverentially from woollies to Warhols and not feel any cultural shift. Shopping is art and art is shopping.

Tonight another cultural milestone of sorts is marked when Madonna announces the winner of this year's Turner Prize at Tate Britain live on Channel 4. The nominees, Mike Nelson, Isaac Julien, Martin Creed and Richard Billingham, have been roundly slagged off by the critics. The Tate must be delirious with the coverage and its PR coup. The usual dinner for the great and the gatecrashers has been replaced by a more "democratic" cocktail party. I couldn't care less. The artists all have something to say – it's how long it occupies my consciousness that's the issue. But I do find something depressing and cynical about the choice of Mrs Ritchie to dish out the honours. How do they top this next year? The Tate has embarked on a rollercoaster ride in its desperate attempt to be bigger, better and more controversial every time. Even second rate art is worth better treatment than this.

Mind you, there seems to be a trend starting. The ICA has announced that the judging panel for the prestigious Beck's Futures Prize (worth £65,000) will include Marianne Faithfull. It can only be a matter of time before this paper replaces our art critic Charles Darwent with Robbie Williams and Rosie Millard stands aside for Denise Van Outen to enlighten us about Vermeer. Commenting on the visual arts is now considered about as intellectual and stimulating as singing the lyrics to "Material Girl". But then I'm a well-educated snob, so I would say that, wouldn't I?

'The Harvard Design School Guide to Shopping', published by Taschen Books, £30. (www.taschen.com) The Turner Prize: at Tate Britain to 20 January