YOU KNEW that Baz Luhrmann understood "The Great Gatsby" when he delegated the music to Sean Corey Carter.

A man from humble origins whose idea of himself transcended his upbringing, who devised a life that matched his grand vision of success, and who became a Big Pimpin' icon.

James Gatz reinvented himself as Jay Gatsby. Carter became Jay-Z.

He's musical host for Luhrmann's big 3-D extravaganza, where Jazz Age flappers dance to hip-hip, not because the music belongs in the roaring twenties, but because it doesn't. The point is that in America, there will always be another Gatsby, another compulsive striver, another party.

And another film director trying to figure out how in God's name to adapt this notoriously unfilmable novel - unfilmable because we read it mainly for the way F. Scott Fitzgerald strings words together: "Gatsby believed in the green light, the orgastic future that year by year recedes before us."

I wonder if this is why studios "green light" such colossal gambles as this one, a $130 million version of a 180-page book - a grand, Gatsby-esque leap at the unattainable.

No expense was spared - Luhrmann commissioned lavish replicas and embellishments of jazz age fashion and baubles. Miu Miu, Prada, Tiffany jewelry. Several hundred Brooks Brothers suits and 1,700 accessories. He created a digital 1920s Manhattan of half-finished skyscrapers, put period first-edition books on the period end tables.

Great gobs of time and energy went into haircuts - a stylist explains that Gatsby's haircut should "effervesce status and wealth."

What would Fitzgerald think of this excess? Well, he was a motion picture nut who'd be thrilled that people were still making movies from his books, but he'd probably barf to find that people were using "effervesce" as a transitive verb.

Or maybe he'd be throwing up because he'd been to a party like the one Luhrmann throws in "Gatsby."

Throbbing Jay-Z beats, $2 million in diamonds, an equal amount in clothes, champagne fountains and Busby Berkeley fan dancers, drunken pool diving, in saturated color and 3-D. But the party has to be big - mysterious millionaire Jay Gatsby (Leonardo DiCaprio) wants it to be seen across the bay by Daisy Buchanan (Carey Mulligan), the woman he loves, now unfortunately married to a two-timing, old-money boor (Joel Edgerton).

"Gatsby" has the feel of a Luhrmann movie - its stylistic gestures are bigger than its emotional reach. But it's not out of step with Fitzgerald, who himself allocated several pages of gaudy description to one of Gatsby's shindigs. Pure showing off. The book is fun to read (until people start dying), and the movie should be fun to watch.

But all of Lurhmann's grand flourishes can't overcome the fundamental problem that all directors eventually face.

Gatsby lingers in our imagination because he's one of literature's great ciphers. When the facts of his life are revealed, it's a soap opera so ridiculous only the author's dazzle can keep us straight-faced. And Gatsby's great love, the cornerstone of the developing tragedy, is over five years before the story begins.

The character most available to us is the narrator, Nick (Tobey Maguire), who describes what he guesses Gatsby and Daisy to be feeling. A truly radical adaptation might eliminate the intermediary, give us Gatsby in linear biography - farmboy to adventurer to officer to bootlegger. Or a director might ditch the ending and turn the whole thing into a romcom - what "Wedding Crashers" did, if you think about it.

But then you'd lose the voice, the point of the view of the man so famously "within and without" the world of privilege and stupid excess - a man disgusted at Gatsby's careless extravagance, then admiring of his American gumption. Who came to see that for Gatsby, money was mere fuel, firing an engine of desire and ambition.

You hope DiCaprio could furnish some of this in his performance, but he does no better than Robert Redford in the '70s version - he's rarely more than a handsome guy in a pink suit, posing next to a yellow roadster. Mulligan struggles to make Daisy register as the object of Gatsby's raging obsession.

So you end up with 3-D images, 2-D characters. Another swing and miss at Fitzgerald.

But that, in a way, is the most Gatsby-ish thing about it. To go all in, to come up short, chasing an impossible dream.

Gatsby was, after all, America's first epic fail.

And do we really want the movies to conquer this elusive book?

An unfilmable novel is an enchanted object, and a great "Gatsby" (apologies to the author) would reduce our count of enchanted objects by one.