Killing Joke.(Joel and Ethan Coen)

The Coen brothers' "No Country for Old Men" casts an ominous and mournful spell from the first shot. Over scenes of a desolate West Texas landscape, an aging sheriff (Tommy Lee Jones), ruminating on the new viciousness of crime, says that he's not afraid of dying. But, he adds, "I don't want to push my chips forward and go out and meet something I don't understand. A man would have to put his soul at hazard." Without transition, we see Anton Chigurh (Javier Bardem), an odd-looking man in a modified Prince Valiant haircut, murder first a deputy sheriff, then a stranger whose car he needs. (He strangles the deputy and shoots the stranger with some sort of gun attached to what looks like an oxygen tank.) The movie jumps again, to Llewelyn, an early-morning hunter (Josh Brolin) who's out in the desert tracking antelope. In the distance, he sees five pickup trucks arrayed in a rough circle and some dead bodies lying on the ground. He moves in slowly, rifle held low. His attentiveness is so acute that it sharpens our senses, too.

In the past, Joel and Ethan Coen have tossed the camera around like a toy, running it down shiny bowling lanes or flipping it overhead as naked babes, trampolined into the air, rise and fall through the frame in slow motion. Now they've put away such happy shenanigans. The camera work and the editing in the opening scenes of "No Country" are devoted to what the hunter sees and feels as he inches forward: earth, a brush of wind, and the mess in front of him, the remnants of a drug deal gone bad. So powerful are the first twenty minutes or so of "No Country"--so concentrated in their physical and psychological realization of dread--that we are unlikely to ask why Chigurh kills with a captive-bolt gun (the kind used in killing cattle) rather than a revolver, or if it makes any sense for Llewelyn, a likable welder and roughneck, to return to the scene with water for a wounded man after he's made off with two million dollars in drug money. "No Country" is based on Cormac McCarthy's 2005 novel, and the bleak view of life that has always existed in the Coens' work merges with McCarthy's lethal cool. After these initial scenes, Chigurh poses hostile and unanswerable questions to the baffled owner of a roadside gas station (Gene Jones), and the mind games are prolonged to a state of almost unbearable tension. Watching the movie, you feel a little like that gas-station owner--impressed, even intimidated.

That's a strange way to feel at a Coen brothers movie. For almost twenty-five years, the Coens have been rude and funny, inventive and tiresome--in general, so prankish and unsettled that they often seemed in danger of undermining what was best in their movies. Have they gone straight at last?

The Coens form a conspiracy of two--industrious, secretive, amused, and seemingly indifferent to both criticism and praise. Early in their careers, they gave detailed interviews, but in recent years they have discussed only specific and relatively trivial matters concerning their movies, avoiding comments on larger meanings or anything approaching a general intellectual outlook. This strategic reticence--the avoidance of art talk--is solidly in the tradition of American movie directors' presenting themselves solely as pragmatic entertainers. But the Coens have gone further into insouciance than any old-time director I can think of. In the opening titles for "Fargo" (1996), they announced that the movie was based on a true story, though it wasn't. "O Brother, Where Art Thou?" (2000) begins with a title stating that the movie is "based upon 'The Odyssey' by Homer," which they later claimed they had never read. From the beginning, they've been playing with moviemaking, playing with the audience, the press, the deep-dish interpreters, disappearing behind a facade of mockery.

Consider a key moment in their first film, "Blood Simple" (1984). Two adulterous lovers, Ray (John Getz) and Abby (Frances McDormand), frightened and at odds with each other, are standing at a screen door. As they talk, we see something flying end over end toward them. It hits the door with a thwack, but turns out to be just the morning newspaper. "Blood Simple" is the kind of adultery-and-murder story that James M. Cain would have written in the nineteen-thirties and Hollywood would have made a decade later into a seductive work of cinematic nightshade--the kind of picture that, as James Agee put it, lulled the audience into "a state of semi-amnesia through which tough action and reaction drum with something of the nonsensical solace of hard rain on a tin roof." There's no such solace in "Blood Simple," which was shot not at night in the labyrinthine big city but in the glare of rural Texas.

That thwack gave the audience notice that the Coens were going to pull at any rug it might be standing on. For example, the romantic attraction between the lovers, which sets the story in motion, doesn't mean a thing; it's completely without heat. What interests the Coens is how foolishly people behave, and how little they understand of what they're doing. The lovers keep misreading signs, misperceiving what's going on. The Coens may be the first major filmmakers since Preston Sturges to exploit the dramatic possibilities of stupidity. In Sturges's movies, however, you don't feel that the rubes and yokels are being put down. Sturges was an affectionate satirist of gabby democratic vitality, but the Coens can be sardonic, even misanthropic. In their world, stupidity leads to well-deserved disaster. In "Blood Simple," the cuckolded husband (Dan Hedaya) hires a vicious private eye (M. Emmett Walsh) to get rid of his wife and her lover, but the private eye double-crosses the husband, killing him instead, and sets up the lovers to take the fall. He laughs to himself, enjoying what a bad guy he is, but then, chasing Abby, he reaches out of a window and into an adjacent one, only to get his hand tent-pegged to the sill by her knife. The Coens spread dark blood on the floor in a spirit of play. Even fans of the movie (including me) came away feeling a little wounded.

If "Blood Simple" suggested that the Coens didn't want to make a thriller so much as tease one into existence, "Miller's Crossing" (1990) sported with the form in heavier and grimmer ways. The movie is set during Prohibition, in a nameless, sombre-looking city dominated by Irish and Italian gangs. The openly corrupt atmosphere and much of the slang ("What's the rumpus?") come out of Dashiell Hammett's novels "Red Harvest" and "The Glass Key," as does the hero (Gabriel Byrne), a morose, alcoholic, and mysterious loner who plays the gangs off against each other. Shot in sullen browns and greens, "Miller's Crossing" begins as a rapturous Bertoluccian piece of filmmaking, and, with the Gabriel Byrne character front and center, the Coens seem to be saying, or confessing, something about the inability to express feeling. But the situations and the dialogue are so stylized--so manically fretted with crime-genre allusions and tropes--that the Coens killed whatever interest we might have taken in their story or in their hero. Perversely, they invented a new form of failure, acting in bad faith toward themselves.