So it was in a black mood that Lucas arranged to meet his wife, the film editor Marcia Griffin, for a quick dinner between work shifts at the Hamburger Hamlet in downtown Hollywood. What both of them had forgotten amid the strain of their hectic schedules was that Star Wars was premiering that very night at Mann's Chinese Theater, just across the street from the restaurant, and as they sat down, they couldn't help noticing the vast crowds jamming the pavement outside the cinema.
The lines didn't abate, that night or any other night for months and months to come. They snaked around the block in cities across the world. Almost in spite of himself, Lucas had launched a phenomenon that was to break all box-office records, invent an entirely new vocabulary for making and marketing films and introduce the world to the true modern meaning of the word "blockbuster".
The crowds didn't let up for the two Star Wars sequels, The Empire Strikes Back and Return of the Jedi, and they kept clamouring, whether it was for the merchandising for the series, the interactive toys, the novelisations, the videos, or the digitally enhanced re-release of the trilogy two years ago, timed to mark the 20th anniversary of the original Star Wars.
And now The Force is about to be with us once more, this time in the form of a brand new Star Wars movie. Star Wars: Episode 1 - The Phantom Menace opens in the United States on 19 May (16 July in Britain), but already it feels as though it has been with us for months. When the first trailer was shown in cinemas last November, it provoked a stampede of such dimensions that several hundred die-hard fans paid the full price of a ticket just so they could relish the two-minute glimpse of pleasures to come. When the second trailer was posted on the internet last month, it scored 3.5 million hits in the first five days.
In San Francisco - George Lucas's home and the site of the first Star Wars preview 22 years ago - fans are anxiously waiting to find out which cinemas are going to book the film so they can start queuing a month ahead of time. Some are even looking for corporate sponsorship to cash in on the publicity that their peculiar pavement sit-in will inevitably generate.
Lucas himself has milked the anticipation for all it is worth, leaking crucial details about the plot, special effects and production of the new film on the official Star Wars website. Now it is almost impossible not to know that The Phantom Menace is the first of three projected "prequels" to the original trilogy, that it stars Ewan McGregor and Liam Neeson, that it is directed by Lucas himself (unlike the second and third Star Wars films, which he merely produced), and that it charts the story of Luke Skywalker's father Annikin as he falls from grace and turns into the evil Darth Vader.
Hollywood loves a sure winner, and winners don't come much surer than this one. It isn't so much a success story as a case of mass hysteria. To predict that The Phantom Menace will overtake Titanic to become the most profitable film of all time is to predict nothing at all in the minds of most film industry executives: for them, the only real questions are whether the film will manage to earn 100 million dollars on its opening weekend, a feat never before achieved, and whether its total gross receipts will hit the near-mythical target of one billion dollars - equivalent to the US takings of the first three Star Wars movies combined.
The unanswered question behind the Lucas phenomenon is: Why? Why has he touched such a nerve in the popular imagination? What is it about the films that people, and especially young people, find so irresistible? In the 1970s, explanations were readily offered: Lucas was uncannily in touch with his own adolescent self and thus with all adolescents everywhere; Star Wars represented a return to the simple moral paradigm of good and evil after the uncertainties of the Vietnam war and the dark ambiguities of the films of Coppola, Altman and Scorsese; in its depictions of youthful vigour without sex, war without perceptible violence and technical wizardry without Brechtian guilt, it even heralded the political conservatism of the Reagan era.
Whatever you make of such theories, they don't begin to explain the enduring appeal of the series into the 1990s, let alone the new, as yet unseen film whose attraction seems to reach way beyond such banal considerations as its actual content. If Lucas has plugged into the zeitgeist this time, it is perhaps in his ability to provide reassurance and familiarity at a time of millennial anxiety. Or maybe what he satisfies is our abstract hankering after an "event", our desire to turn a cultural artefact into a grand occasion.
"We have moved into an obsessed world, and maybe this is the acme of it," says Leo Braudy, a professor of English and popular culture at Lucas's alma mater, the University of Southern California. "Obsession has become the preoccupation of the age, and the internet feeds and structures this obsession. Whereas passion for a movie, or collectables, or comic books was something haphazard and personal in the past, now it has become institutionalised, with thousands or millions of people out there to share it with."
Despite Lucas's reputation as a visionary, these are cultural forces that seem to dwarf him. Indeed, he represents something of a paradox: a shy, unassuming man, more dogged than bright, who stumbled on to fame and adulation without much apparent aptitude and, certainly, without the stomach to relish it. By all accounts, Lucas is a painful communicator, has difficulty relating to actors or even crews, suffers headaches and stomach aches when he writes screenplays and hates directing because it exposes him to so much stress and fear of the unknown.
For him, the first Star Wars meant almost unceasing pain, from the torturously slow writing process in a cabin in northern California during which he obsessively snipped off locks of his hair, to the initial rejections from United Artists and Universal, to the uncomprehending reactions of friends such as Francis Ford Coppola.
The cinematographer Haskell Wexler, Lucas's first friend in Hollywood who helped get him into film school at USC, turned down the chance to shoot Star Wars because he didn't understand the script - at that stage a mishmash of plotlines, half-formed characters and gobbledegook about padawaan learners and Jedi. "I couldn't figure out what the hell it was about. I told George, you have to get some humanity into this thing," Wexler said.
The only reason Star Wars got the green light at all was because Alan Ladd Jr., head of production at Fox, loved Lucas's previous hit, American Graffiti, and was prepared to shell out 3.5 million dollars on the new film, whatever it was. An uncomfortable shoot in Tunisia and London inflated that price-tag to 9.5 million, which was still too little and caused Lucas to cut every corner in the book.
His actors found the dialogue bizarre (Carrie Fisher, who played Princess Leia, called it "space triple-talk, killer lines") and his direction bafflingly curt (his only instruction seemed to be "do it again, this time better"). His crews found him authoritarian and overbearing, giving him a toy Hitler moustache at the end-of-production party. In short, everyone believed they were involved in a total turkey.
What Lucas had in his head, and nobody else could guess at, was a strikingly clear and original visual sense of where he was going. The film, like much of his subsequent work, came together in post-production, largely thanks to the contribution of his fledgling special effects company, Industrial Light and Magic. The result may not have been an enduring masterpiece but it had, in the words of Sir Alec Guinness who played Obi-wan Kenobi, "a freshness; also a sense of moral good and fun".
Lucas's real coup was not so much artistic as commercial. He had the foresight to relinquish a higher director's salary in exchange for the rights to sequels and merchandising - contractual talking points that in 1977 were considered well-nigh worthless. When Star Wars charged into the box-office stratosphere, these talking points turned into gold dust and Lucas was given the foundation stone of a movie empire free of all constraint or big-studio control.
There are those who blame Lucas and Star Wars for the end of intelligent film-making in Hollywood and the advent of the blockbuster mentality that has encouraged studios to put all their investment into big-budget action films and their sequels while neglecting more prestigious, character-driven projects. Certainly, Star Wars showed what special effects could do. Certainly, it revolutionised the marketing of big-studio films; Lucas let the studio know that the mega-audience was out there, and the studios responded by launching big films with massive first-weekend releases supported by saturation television advertising, effectively squeezing out the smaller stuff.
But these are forces greater than any individual. The Star Wars phenomenon is in many ways independent of Lucas; it has taken on a life of its own - one that has appalled many involved in its making. "I have no intention of re-visiting any galaxy," Alec Guinness declared a few years ago after meeting one obsessed Star Wars fan too many. "I shrivel inside each time it is mentioned."
In the industry, it is not fashionable to give Lucas much creative credit these days, even among film-makers who use the sort of special effects that he and Industrial Light and Magic pioneered. "Many of the technical tricks he came up with were a result of his own hatred of the encumbrances of film-making," said Bill Pope, cinematographer on the new hi-tech Keanu Reeves vehicle The Matrix, which is heading for blockbusterdom in the States. "Lucas is so inarticulate, so uncomfortable with people, he'd much rather be making a digital cartoon. Most people, though, still believe in making films with people, not just machines."
For Lucas himself, the Star Wars series represents a curious defeat. Once he'd made his fortune and become artistically independent, he dreamed of returning to smaller projects. But he was unable to get anything off the ground. More American Graffiti, a sequel to his earlier film, was a flop. After the Star Wars trilogy, he produced the Indiana Jones films for Spielberg - another big, if highly accomplished, step towards turning film into a glorified comic- strip for mass consumption.
Then came Tucker, an ill-fated collaboration with Coppola, and the excruciating Howard the Duck, then nothing. Lucas seemed overwhelmed by his own legacy, and grew ever more defensive about the charge that he and Spielberg had "killed" intelligent movie-making. He argued that he had in fact paved the way for the independent movement and given cinema owners the financial resources to build more screens to show more off-beat material.
The argument may have some merit, but it is also tinged with a sense of disappointment at his failure to produce that challenging material himself. Lucas looks like a man trapped by his own legend and his own limitations. Having agreed to make the three Star Wars prequels starting with Phantom Menace, it seems he faces the prospect of further adulation and untold riches with resignation rather than enthusiasm. "It took a long time for me to adjust to Star Wars," he has said. "I finally did, and I'm going back to it. Star Wars is my destiny."