First we had to get used to the idea of apartments - and that took decades. Now, Ireland is frenetically embracing the notion of penthouse living. Where once the very notion of the top floor suggested maids' quarters and somewhere to sling the suitcases, today there is simply nothing smarter than hitting the heights.
Top floor is top drawer. Dublin 4 is about to get its very first high-rise apartment building - overlooking the Grand Canal basin in Ringsend - and property pundits predict many more will follow. Until recently, the word high-rise automatically suggested social deprivation. Now people are queuing up to live in towers where the best and most expensive flats are at the very top.
A penthouse doesn't have to be in a tower block, however. In the current property boom, even the tiniest attic space can be reborn as a penthouse, however cramped the conditions. Originally the term was used only to describe the upper reaches of a very tall building. However, at the moment, even two-storey buildings somehow manage to boast of a penthouse - if not several, while humble houses that have been carved up into flats are suddenly acquiring penthouses too.
Property developers love penthouses. They sound so cosmopolitan and they are worth at least 20 per cent more than their lowly equivalents elsewhere in the building. And city dwellers covet them too, even if it means hauling beds up five flights and constant worry that the dog will accidentally leap into oblivion. Get rid of the pet - and most of the furniture - and suddenly penthouse life seems wonderfully feasible, if rather expensive.
Owning a penthouse shoots one up into high-rise society, preferably via a private lift. There is a certain raciness about living at the top, far away from the lower orders and their petty squabbles over junk mail and rubbish collection.
The penthouse dweller is invariably not at home for these discussions, being out of the country or in the depths of the country, depending on the time of year. He or she slips in and out of his pied au ciel now and then, throws a party when the view is at its best and lends it out occasionally to visiting friends and clients - with the housekeeper thrown in, of course. Or at least that is what some people who own penthouses do, provided they can find the right property. There are penthouses and penthouses, and not many of them measure up to expectations. The grand old penthouses, as seen in early James Bond films, were usually light-filled, glass-walled homes with vast terraces, suites of rooms and cocktails on tap - you felt shaken and stirred by the sight of so much airy splendour. Palatial properties, raised high above everyone else's aspirations, their occupants were permanently tuxedo-clad or dressed from head to toe in sequins and marabou, able to top up their tans by stepping out onto a balcony for five minutes.
Ireland's new penthouse dwellers are not quite in the same league.
They are as likely to wear denim as dinner jackets and they come from all walks of life. The penthouse at Merrion Village which changed hands some months ago for a staggering £730,000 was once owned by Dunnes Stores millionaire Margaret Heffernan. Now it belongs to Robbie Dolan, a thirtysomething businessman who sells gym equipment. Many newly built penthouses are snapped up by anonymous investors, people who never intend to live in them, but who will rent them out, keep them as a pension, or have them as somewhere for the kids to live when they go to college.
The one common denominator among penthouse dwellers is that they have enough cash to pay a premium price and want everyone else to know it; living at the top is a very public statement. This is one way to guarantee a high profile - literally.
Even if the contemporary penthouse is often much smaller than its predecessors, it must have certain features to qualify for the name. Obviously it has to be on the top floor, although some developers like to adopt a staggered effect with several penthouses jostling for that upper slot on a building. It should also have a degree of privacy, and preferably access to a roof terrace or even a garden - a couple of window boxes are definitely not enough.
Inside ought to be fairly open-plan and uncluttered, not lots of little, busily-arranged rooms decorated with dado rails and flowery wallpaper. There is something very peculiar about imposing the country house look on what, in effect, is a steel box in the sky. Lots of windows are desirable to give the penthouse that essential airy, top-of-the-world feeling. This cannot be achieved when the builder is squeezing the "penthouse" beneath a mansard roof with awkwardly-sited dormer windows, making it a liability for anyone much over five foot tall.
Living at the top is currently the sine qua non of stylishness - but how long will this last? After all, not so long ago, nothing was considered smarter than owning a neo-Georgian property in the suburbs. Now city-centre properties are far more fashionable. However, with rising levels of pollution and an ever-thinning ozone layer, perhaps the disadvantages may come to overwhelm the merits. Who knows; maybe basements (or garden flats as smart occupants have already renamed them) will be the dream homes of the next generation?