Sensational, grandly sinister and not for the kids, "The Dark Knight" elevates pulp to a very high level. Heath Ledger's Joker takes it higher still, and the 28-year-old actor's death earlier this year of an accidental overdose lends the film an air of a funeral and a rollicking, out-of-control wake mixed together. In "The Dark Knight," Ledger makes all other comic book screen villains look like Baby Huey. Like Shakespeare's Iago or Richard III, like Anthony Hopkins' Hannibal Lecter or Javier Bardem's implacable murderer in "No Country For Old Men," this is no Method maniac, asking or telling anyone about his character's motivation. At one point Ledger throws up his hands and says, agitatedly, that it's a waste of time looking for a rationale behind the Joker's smeary psycho-harlequin makeup.

"I'm a dog chasing cars," he says. "I wouldn't know what to do with one of them if I caught it."

Director and co-writer Christopher Nolan, who fashioned the screenplay with his brother, Jonathan, has created the most ambitious and sleekly beautiful of all the superhero screen outings. A handful of others -- "Superman II" and "Spider-Man 2" come to mind -- may have fewer loose ends and a more exhilarating spirit. They're certainly shorter; this one is 152 minutes. But "The Dark Knight," which improves upon the solemn authority Nolan and Christian Bale's Bruce Wayne brought to "Batman Begins," has an atmospheric shimmer all its own. Its unsung hero is cinematographer Wally Pfister, who makes every interior and exterior a thing of burnished, menacing beauty. Shot largely in Chicago at night, greatly aided by production designer Nathan Crowley, this is the most nocturnally insinuating entertainment since Michael Mann's "Collateral."

Sampling every flat Midwestern dialect he no doubt heard while shooting in Chicago, Ledger gives the Joker the deceptively bland vowel sounds of heartland America. But Gotham City is no heartland paradise. It teeters on the verge of bloody anarchy, and its most outre citizen licks his chops, literally, as if he can't get the taste of blood out of his mouth.

While billionaire playboy Wayne continues his clean-up campaign, Gotham City finds a new symbol of righteous hope, district attorney Harvey Dent (Aaron Eckhart). He has it all: a fervent desire to clean up a dirty town, plus the love and devotion of Wayne's ex, the assistant D.A. and one of a small handful of Gothamites who know Batman's true identity. She's played by Maggie Gyllenhaal, stepping in for (and improving on) Katie Holmes. Gyllenhaal's curled-at-the-corners smile matches up perfectly with Bale's.

The D.A. teams up with Batman and the weary honest cop Jim Gordon (Gary Oldman in a mustache that says "trust me") to combat organized crime, though Batman's vigilantism has inspired all sorts of copycat, low-rent imitators. Then, just when the film needs a good jolt, Dent undergoes a radical physical and psychological transformation and becomes, literally, two-faced.

The transformation comes at a narrative cost. The film's focus is thrown slightly out of whack, and it's too bad his coin-flipping gambit is so like that of "No Country's" Anton Chigurh. Not everything in "The Dark Knight" works: Some of the more painful flourishes -- a grenade plopped in a bank manager's mouth, the terrorization of Gordon's children -- are too much. Yet so much of "The Dark Knight" works on different levels simultaneously. It's a brooding crime saga with some spectacular action sequences. My favorite pits Bale's Batman and his "Bat-Pod," the world's deadliest, most awesome motorcycle, against Ledger's Joker in an 18-wheeler. The setting is Chicago's LaSalle Street canyon, and what I love about the scene -- aside from its eerie, 3 a.m. vibe -- is Nolan's reliance on good old-fashioned stunt work. "The Dark Knight" offers plenty of digital effects, but they never take over.

Nineteen years ago, Jack Nicholson's Joker won a lot of the credit for the popularity of director Tim Burton's "Batman." In contrast to that stylish but uneven picture, one of the splendid things about "The Dark Knight" is its refusal to squander its villain. This is a true ensemble piece, and you can't say that of most $180 million franchise products. Ledger's scenes are few, carefully considered, often startlingly brutal (one scene, over in an eye-blink, involves a disappearing pencil trick and a man's skull) and freakishly effective.

Six sequences constituting about 20 minutes of footage were shot using IMAX cameras, including the opening bank heist and a fabulous swoop across the Hong Kong skyline. (The narrative takes a detour for a matter of extraditing an Asian businessman back to Gotham and to justice.) There's a sweep and spaciousness to the imagery here, and even a simple chase sequence such as the one staged along Lower Wacker Drive feels freshly considered. The violence, however rough, is largely free of the lingering, jokey sadism prevalent in so many comic-book and graphic novel-derived films. Nolan paints an inky portrait of a city falling apart, and in a movie rife with two-faced masquerading freaks, the Joker is merely the least conflicted of the bunch. Ledger's work is improbably droll, impossibly creepy, meticulously detailed. See for yourself.