Is “Burn After Reading” a thriller? A comedy? A sex tale?

Yes, yes and yes, with a dollop of social commentary tossed in . And the latest offering from Joel and Ethan Coen  somehow holds together.

It all starts with gym employee Linda Litzke (Frances McDormand) . She yearns for cosmetic surgery that she believes will enhance her romantic prospects. Because her insurance won’t cover the operations, she looks elsewhere for the money.

A CD containing apparent C.I.A. intelligence data falls into her hands at the gym, causing Linda and her equally air-headed  friend Chad (Brad Pitt) to believe they’ve landed at the end of the rainbow. They decide to blackmail recently canned C.I.A. analyst Osborne Cox (John Malkovich) or,  failing that, to sell the disk to the Russians.

The cast of characters grows to include Cox’s wife (Tilda Swinton), an ice-blooded physician who clearly skipped the class on bedside manner; federal marshal Harry Pfarrer (George Clooney), who sleeps with both Linda and Mrs. Cox when not bedding one online pickup or another; and Linda’s boss (Richard Jenkins), whose love for her is blithely unrequited.

David Rasche and J.K. Simmons, stalwart character actors who are known more for their faces than their names, appear as C.I.A. officers who follow the mysteries and mounting mayhem in scenes that are masterpieces of deadpan. At one point, Simmons directs his colleague to report back “when it makes sense.”

“Burn After Reading” takes its time; it’s no romp except perhaps for the pervasive adultery, and even that lacks spark.

The intersecting storylines are played straight and matter-of-factly, gradually accumulating humorous impact rather than delivering it in one-liners and pratfalls. At bottom, it’s a story of people who are oblivious to conventional morality and can’t seem to help doing one bone-headed thing after another.

The consequences tend to be serious, especially in the case of the two characters who are murdered. Sudden violence is always unsettling in comedy, even ostensible comedy. Amid the straight-faced follies of “Burn After Reading,” however, the juxt aposition is less jarring than usual.

Members of the Coens’ star-studded cast seem to enjoy themselves and, in fact, are largely responsible for holding the convoluted movie together. Pitt displays solid comedy chops as the bird-brained Chad, but the most captivating figure is Osborne Cox . As the angry, sarcastic, short-fused, boozy and foul-mouthed C.I.A. man — arguably the film’s only true victim — Malkovich steals every scene he’s in.

The Coens set the bar at a lofty height with “No Country for Old Men.” This movie doesn’t aim that high, but it’s an intelligent, involving and darkly funny work that stands out among most Hollywood products and certainly deserves to be seen.