So what's all the fuss about?

High Fidelity was a parochial British novel about a sad and obsessive music nerd. So why are American audiences so keen on John Cusack's film version?

"What really matters is what you like, not what you're like," says Rob Gordon (John Cusack) in the American film version of High Fidelity. Fans of the novel High Fidelity, Nick Hornby's homage to Holloway, can rest assured that even though the new version has been transplanted to Chicago, it is still very much a collectible. The big surprise is that the American version is even better than the novel.

High Fidelity gives a lot of room to the novel's two fan boy bookends - one shy flower, one wise-ass - who work in Rob Gordon's record store, Championship Vinyl. There are still the novel's girlfriends past, itinerised like bottles of fancy beer in a refrigerator. There's still the power struggle between Rob and his long-suffering, strong-willed girlfriend Laura (Iben Hjejle).

New, spot-on Hornby-isms abound (Rob exalts one of his girlfriends for rubbing her feet together in bed) but it's often by the book. The description of Rob's one-night stand, singer Marie LaSalle, is the same in the novel and the film. Hornby dubbed her "post-Partridge Family, pre-LA Law Susan Dey". Here, played by Lisa Bonet, she's said to resemble Susan Dey post-Partridge, "but black". In its rush to stay faithful to the novel, the film even makes a minor mistake - it's far less likely that an American indie rock record store owner would also be a club DJ. But then again, this is Chicago.

Now for the differences. In High Fidelity, the novel, our narrator presented himself in simple-minded fashion. And with this simplicity he wormed his way into the reader's consciousness. High Fidelity the film, on the other hand, is a much more complicated affair. It's got the novel's boppy, post-feminist masculinity. But it's mostly about American fandom.

Like Being John Malkovich and King of Comedy, High Fidelity is about little men-boys with big-taste worlds. Groovy academic Slavoj Zizek has already singled out Being John Malkovich as an illustration of individual consciousness. All three films are mildly eccentric comedies capable of exploring celebrity mania, while reproducing it in a minor key.

Fandom is stardom's shadow, of course, but surprisingly few films have explored the relationship between them (All About Eve being a notable exception). Twenty-five years ago, they didn't need to. Back then, film theorists could muse that stars were over-appreciated pawns who traded in charisma. Stars were seen as powdered figureheads who had no political power - or if they did it was symbolic, as in John Wayne or Jane Fonda, while only the minor stars ran for government office.

How times have changed. One need only think of Leonardo DiCaprio's "press conference" with Bill Clinton last week or even Warren Beatty's threat to run for president to know that not-so-minor celebrities have spilled into the arena of real politics. They copyright their own images. They are traded on a Stock Exchange. They control the press. In short, they have become unregulated commodities.

Meanwhile, ordinary fans are more rabid than ever. Now, fans know the names of producers, back-up singers, stars, bit players and even crew members, the record label in-fighting and the price of cable actors - these days, we're all film critics, we'll all reporters for Billboard and Variety. One would have to be some sort of ruddy pastoralist not to know the box office of Erin Brockovich.

That contemporary reality suffuses our watching of High Fidelity. In a sense, the audience has caught up with Rob Gordon, obsessive fan. By watching VH1 pop-up videos, they soak up all the celeb trivia Rob Gordon has spent his life mastering. An abundance of dispassionate 20-year-olds could tell you how Marvin Gaye died or who were Green Day's influences.

Through High Fidelity, the film, we get a grip on these creatures. Gordon's low-rent Chicago slacker digs resembles a claustrophobic North London flat but its quite poignant to see such an average fan apartment in an American film. The truth of the matter is that "poor" apartments and houses in American films bear a greater resemblance to the celebrity homes profiled lavishly in In Style and architectural glossies - every sullied rapscallion lives in a huge loft, every tawdry hick in an abode worthy of a Tom Waits song for its indigenous, antique wash tub-like charms.

The film's hero may live in an apartment as casually screwed-up as the homes of you and your friends. But he himself is a good deal cuter than he is in the novel - no longer "average height, not slim, not fat" - but now with black mane, rosebud-lips and flashing eyes. Cusack is the most glamorous schlepper anyone can imagine. He is the anti-movie-star movie star, the handsome guy who wants to be a clever, ironised weakling and has played one since he was in his twenties. The contradiction of his star status and his patented role of the lowly fan adds a richly conflictual layer. Like his earlier celeb worshipper in Being John Malkovich, Cusack interprets Rob as a man trying to get inside the portal, this time the headspace of musicians. He listens to his records over and over again, making mixed tapes for girls, reorganising his LPs according to his own biography. For Rob Gordon, to be in the audience is not enough - he is, like today's audience, a most aggressive entertainment consumer.

Another change for the better is that the American Rob was forged in the US's late Eighties college rock scene. He's not so into soul music (all those gratuitous R&B references, they're gone, thank God), but he is a dated creature - of the American variety, the slacker.

As in Being John Malkovich, where Cusack looked exactly like the ultimate Gen X novelist David Foster Wallace, slackerdom acts as the film's shorthand.

How else could these films so easily justify hero Cusack's insolence and also submission to pop celebrity? What other American middle-class youth, besides my aging cohort, would agree to live in a community of underemployed, uncertified Simon Frith wannabes, clinging to the split dream of total stardom on one hand and an unco-opted indie rock subculture on the other? High Fidelity: it's a window into our sad American souls.

In the spirit of Rob, here are the Top Five Most Obvious Bits of Americana in the movie 'High Fidelity':

No audible Joni Mitchell.

The vast record store with its party! party! sofa in the backroom.

Rob's early girlfriends, who look like bit players in such all-American films as 'Bad News Bears' and 'Grease II'

The presence of indie-film queen Lili Taylor

Hattie Jacques reference deleted

'High Fidelity' goes on general release from 21 July