Whatever their quality, the Coen brothers' pictures usually tend to include two distinct ingredients, which sometimes overlap: a considerable amount of bloody, sometimes gratuitous violence, and a certain sneering contempt for the audience. They often occupy an invulnerable position, implying an additional disdain for their work, which deflects criticism - if they don't take their movies seriously, they suggest, then nobody else should, either. When in doubt, they go not for the jugular, but for a laugh.

Their success with "No Country for Old Men," however, also showed that with an excellent fictional source and a faithful adaptation, the Coens could make a powerful film, which though extremely violent, displayed a completely sincere approach to its action, characters, and themes. Although they reverted to form with last year's "Burn After Reading," their latest movie represents something like a departure from the past, a move in a new direction with a very different kind of comedy from their characteristic wiseass gags and lines.

"A Serious Man" unfolds from a beginning right out of some folk tale, with a Jewish couple in some undetermined time and place receiving a visit from a dybbuk, the ghost of an old rabbi, an occasion that apparently curses their family. That entirely isolated incident, never referred to again, provides the only hint of motive for all the disasters that befall the protagonist, Larry Gopnick (Michael Stuhlbarg). The picture opens all over again in the late 1960's in a college lecture hall, with Gopnick, a professor of mathematics, covering an enormous blackboard with an immensely complicated, wholly incomprehensible series of equations, and gushing over the result, the work of the physicist Schrödinger.

After his class and a confrontation with a Korean student arguing for a passing grade, Larry drives to his home in one of those horrible cookie-cutter suburbs, where all the houses conform to the same dreary pattern, and all the colors, even of the earth and sky, wash into a dull palette of pastels. Larry must deal with a family whose dysfunction he never realizes - a stoned son studying for his bar mitzvah, a whiny teenage daughter who mostly devotes herself to washing her hair and wishing for a nose job, and a sponging loser of a brother, who sleeps on the living room couch and spends most of his time nursing his various ailments.

Larry's world begins to crumble when his wife, Judith (Sari Lennick), informs him that she wants a divorce so that she can marry a family friend, the oleaginous Sy Ableman (Fred Melamed); Sy and Judith also expect Larry to pay for the ritual divorce their devotion demands. That announcement precipitates a series of small and large calamities in Larry's life - an automobile accident, a property dispute with a belligerent, gun-toting neighbor, his brother's arrest on never-explained charges of solicitation and sodomy, anonymous letters to the committee deciding on his tenure at the university.

His financial and legal woes force Larry to consult three different lawyers; his desperation leads him to three different rabbis - none of these individuals provides any solutions or consolation. Like Job, surely the model for his character, he finds no explanation for all his misfortune and pain, which, after some alleviation, actually grow worse, as the movie concludes with the promise of further disasters to follow.

A number of mostly unknown actors play the major characters with a naturalism and authenticity that seldom even looks like acting; they seem, in fact, exactly the people they impersonate, a remarkable exercise in the ordinary. Michael Stuhlbarg, whoever he is, displays the anguish of this essentially well meaning, much abused, absolutely puzzled man who for no good reason becomes the victim of both fate and his friends and family, never deserving the pain he endures, never understanding why he should endure it. Strange as it may seem, "A Serious Man" plays much of its sorrow for laughs, and much of it, believe it or not, justifies the laughter. At the same time, without any bloodbaths or blatantly evil characters or actions, the movie may be even bleaker and more despairing than the Coen brothers' best film, "No Country for Old Men," a most distressing kind of comedy.