In his classic Los Angeles: the architecture of four ecologies (1971) - the book that launched the continuing British fascination with LA, which remains one of the best accounts of the place ever written - Reyner Banham relegated the downtown quarter of the city to a mere afternote. It was, he declared, 'all that downtown Los Angeles deserves. . . in terms of the real life of the 70mile-square metropolis today, most of what is contained within the rough central parallelogram of the Santa Monica, Harbor, Santa Ana and San Bernardino freeways could disappear overnight and the bulk of the citizenry would never even notice'.
Norwich-born Banham had to learn to drive to research his book: 30 years later, a car is still an essential adjunct to normal life in the City of the Angels.Automobile culture remains strong, yet the talk in LA today is increasingly about city-centre living, increased densities, conservation (both of scarce energy and of old buildings) and, yes, public transport.
Last summer, the Red Line of the LA Metro system - launched just 10 years ago - opened between downtown LA, Hollywood and the San Fernando Valley. By 2010, it is projected, half a million of the Pacific Rim metropolis's commuters will travel to work by train.
Already the generator of an impressive public art programme, the Metro - a mix of light rail and subway technology - has commissioned at least one outstanding station (Vermont/Santa Monica, by Merhrdad Yazdani of Ellerbe Becket, with a landmark 'floating' entrance canopy). Even more exciting is the proposal for a pedestrian bridge commissioned by the Metropolitan Transportation Authority from Morphosis, probably LA's most cutting-edge practice.
LA is too diverse and fragmented a conurbation to ever have a single centre, yet downtown LA, for all Banham's dismissive comments, survives as a vibrant city district of a sort easily recognisable to Europeans and East Coast Americans. Broadway, LA, has become the central hub of what Mike Davis calls 'the Latino metropolis'. Its extraordinary heritage of theatres and cinemas has been rescued from dereliction by reuse as gospel halls and ethnic movie houses for the Hispanic population.
The nearby historic (that is, 1900 onwards) business district went into rapid decline after a new commercial quarter was developed on Bunker Hill after 1950. Today, the substantial 10 to 12-storey blocks here are in huge demand - Historic Downtown is becoming a place to live. Last month, developer Mark Weinstein announced plans to convert 10 vacant blocks into 400 apartments, plus bars, shops and restaurants.
Large chunks of the central core have reportedly been snapped up by property interests convinced that LA wants downtown lofts. Since my last visit in 1997, an intensive municipal campaign has reequipped much of downtown with decent paving and high-quality street furniture.
Ironically, it was the clearance of the largely residential quarter of Bunker Hill for office towers - of variable quality - that saved Historic Downtown (as it is now officially designated) from redevelopment. The construction of the Music Center in the 1960s and the Museum of Contemporary Art (by Arata Isozaki) in the 1980s were part ofa campaign to give the reconfigured area along Grand Avenue cultural as well as commercial clout. Today, office workers drift downhill to the amazing 1900s Grand Central Market for lunch to escape the sterility of their late 20th century environment.
But huge hopes rest on two great LA projects. After long delays, Frank Gehry's Walt Disney Concert Hall, opposite MOCA, is well under way. The 2,300-seat, US$274 million (£193 million) complex is scheduled to open in autumn 2003. Gehry won the competition for the building in 1988. By 1996, only the subterranean parking levels had been built and a major fundraising campaign was needed before construction of the hall itself could start in 1999.
As part of a redesign operation, the stone cladding originally intended was replaced by stainless steel. The external form of the building might suggest comparisons with Bilbao, but the Douglas fir-lined interior of the concert hall itself, dominated by a huge organ in a case by Gehry, has real West Coast roots in the timber building tradition of Greene & Greene, Maybeck and Schindler.
Gehry is a legend in LA and his earlier works - such as the Temporary Contemporary and Santa Monica Place - have worn well. Architects of the younger generation, such as Michael Maltzan and Hagy Belzberg, who served their time in his office, regard him as a father figure. Belzberg is, however, more excited by Rafael Moneo's new Catholic cathedral of Our Lady of the Angels, which is nearing completion a few blocks north of Disney Hall.
The original cathedral of St Vibiana, a building of no great merit, was damaged in the 1994 earthquake. That event provided the stimulus to efforts to give LA's four million Catholics an appropriately impressive focus. A new site had to be found after the city ruled that the old cathedral could not be demolished - it is being converted into a 'boutique hotel' and arts centre - and Moneo won the commission in 1996.
He was asked to design a 'plain vanilla' cathedral that could be ornamented by fittings removed from the old St Vibiana or by new adornments commissioned when funds were found. His cathedral could be one of the great churches of the modern age, a massive structure of fair-faced, in situ concrete, roofed in timber and copper, set within cloisters and gardens that provide respite from the city streets. Seismically engineered by Nabih Youssef & Associates to withstand the dreaded Big One, the 3,000-seat cathedral is designed to last 300 years.
Permanence was one quality that, until recently, did not cut much ice in LA.
The famous house in King's Road, West Hollywood, designed by RM Schindler, is positively flimsy - it wouldn't last a few years in Britain - but is made for outside living in a balmy climate. Yet neither it nor the equally lightweight Case Study houses provided a model for the aspirational LA home.
Banham loved LA for 'the sense of possibilities still ahead' it conveyed. Until recently, an interest in the past seemed at odds with the genius loci. Landmarks, ranging from the Brown Derby to works by Gill and Neutra, were thoughtlessly razed. Now the emphasis is increasingly on restoring and reusing - the recent revamp of the splendid Pantages Theatre on Hollywood Boulevard mixes strict reinstatement and free invention to magical effect.
Just down the road, developer TrizecHahn's US$600 million (£422 million) Hollywood & Highland development includes a permanent home for the traditionally itinerant Oscars ceremony.
Aficionados of the city might find this trend worrying: LA is increasingly selfaware and concerned about its image, hence the huge programme of landscaping, signage and public art at LAX, the region's international airport.
The most monumental of the region's building projects of recent years, Richard Meier's Getty Center, was overshadowed, perhaps, by the huge international success of Gehry's Bilbao Guggenheim. Gehry, the king of LA architecture, should have got the job, some said.A few years later, however, the real dignity and compositional sophistication of Meier's 'hill town' impresses, with the large areas of stone cladding giving it a look of, yes, permanence. I loved the old Roman Villa Getty, but Meier's Center is a masterpiece in its own right.
For an even greater masterpiece, however, visit Robert Irwin's central garden. Here, among the flowing water, the roses, hibiscus, bougainvilleas and lilies, you realize that the Californian dream is as potent and (to European eyes) just as exotic as ever.