Everything about An Education, the story of a 16-year-old girl's affair with a 30-year-old man in London in 1962, comes together in a way that gives the movie the feel of an instant classic. There are the sparkling performances by Carey Mulligan as the young and impressionable Jenny and Peter Sarsgaard as the shady hustler David; the precise costuming and set design and lovely cinematography; the urbane script by novelist Nick Hornby (High Fidelity) and the elegant and invigorating direction by Denmark's Lone Scherfig.

You can almost imagine the makers of An Education, which opened Friday, busting out the champagne and toasting their genius when the movie was finished. But when Hornby and Scherfig traveled to the Sundance Film Festival in January hoping to land a U.S. distributor, they weren't entirely sure how their trip would turn out.

``I'm a terrible judge of my own work,'' Hornby says. ``I just always presume people aren't going to like anything. You lose a sense of perspective while making a movie, and I didn't know how people would respond to the questionable nature of the material.

``And I didn't know how people would respond to Carey, either. We all loved her as a person, so when we watch her on the screen, that's who we see. But we didn't know how that would translate to other people. And if you don't like Carey, you don't like the movie.''

But Hornby need not have worried. An Education ended up wowing Sundance, winning the Audience Award for Best Drama and Best Cinematography for John de Borman. It also snagged a distribution deal with Sony Pictures Classics -- and has since been sold for release around the world.

SHE'S A STAR

And practically everyone who sees An Education falls in love with its British star, the 24-year-old Mulligan, who is quickly becoming the one to beat for next year's Best Actress Oscar (sorry, Meryl).

The movie was born in the pages of Granta magazine in the spring of 2003, when Lynn Barber published a 10-page autobiographical essay about her adolescence titled ``An Education.'' ``The more I thought about it, the more everything about my life as a teenager seemed odd,'' Barber wrote last August in another article pegged to the film's release. ``Why was I, a conventional Twickenham schoolgirl, running round London nightclubs with a conman? Why did my parents let me? Almost to explain it to myself, I wrote down everything I could remember and found that, once I tapped this untouched spring of memory, there was no stopping it.''

Hornby says when that he read Barber's essay, he immediately turned to his wife Amanda Posey, an independent movie producer, and said, `` `I think you should do something with this.' It seemed very rich material. She asked, `I don't suppose you want to write it?' and I said no. But when they came to talk about writers, I found I was getting possessive and asked if I could do it.''

Although he traditionally writes about male characters in his novels, Hornby says he was attracted to An Education because of its classically simple structure, which provided a lot of room for a movie to expand upon.

UNFAMILIAR PLOT

``These were people I had not seen on screen before, particularly that Bohemian underworld Jenny falls in with after she meets David,'' Hornby says. ``The piece was painful, but it was funny as well. I liked what it has to say about one's relationship with stuff, almost in a High Fidelity way, that this girl was very hungry for music and movies and art. I really identified with the suburban kid who is frightened she's going to get cut out of all that stuff.''

Hornby and the producers collaborated with British filmmaker Beeban Kidron on the project, but she eventually had to leave the film due to another contractual obligation. Enter Scherfig (Italian For Beginners, Wilbur Wants To Kill Himself), whose enthusiasm for the project landed her the gig.

``Nick and I have the same agent, so we met each other that way,'' Scherfig says. ``The way he combines humor with this profound affection for his characters is something I can really identify with. And it was an advantage not being British, because it forces you to see things from the outside and not take anything for granted and emphasize all the layers.

``The details of the era are very necessary to this story. These characters are connected to their time and the English caste system and English identity. Not being a part of that culture forces you to analyze things more thoroughly.''

Shot for a modest $8 million, An Education still manages to recreate the look and mood of a pre-swinging, still-sleepy London with unusual veracity.

``It helps that the British are really conservative and good at maintaining buildings,'' says Scherfig, a disciple of the Dogme filmmaking movement that requires directors to use existing locations and natural lighting as much as possible. ``You can just go out and shoot things the way they are, even though the film takes place 50 years ago.''

NIGHTLIFE ALLURE

More important than London by day, however, was London (and Paris) by night, where Jenny is seduced by the allure of swanky jazz clubs and fancy restaurants and ornate theaters -- a world she only knew existed from books before she met David.

``When Jenny comes home after her first date with David and tells her mother `It was the best night of my life,' you buy that,'' Hornby says. ``It was pretty much the best night of my life just watching it -- to be a teenager and go into those clubs and eat that food and meet those people. How high a price would you be willing to pay at that age?''

The viewer's desire to be part of that world along with Jenny -- who wouldn't? -- helps make the central conceit of An Education more palatable and less thorny. This is no mere Lolita redux: The relationship between the teenage girl and the man is much more complex than normal for this kind of tale.

``Peter's performance [as David] really walks a fine line: We are charmed by him right along with everyone else,'' Hornby says. ``And it's important to the movie's sense of comedy that Jenny is never a victim. We were very careful with that. She chooses when she loses her virginity. She chooses when she gets in his car. Even when they kiss, it is her making the move toward him. She's really smart and in control, so you don't become as fearful for her as you otherwise might.''

Despite all the critical raves An Education has received, Scherfig admits there was one review more important than any other.

``Lynn Barber has led a really colorful life,'' she says. ``She's even written two sex manuals: She's much more extreme and liberated than our Jenny. I've met her twice, at screenings of the film, and both times she had a smile that went all the way up her cheeks. She's strong, she's really happy, and she's been inspired about all the fuss that's being made about her now.''