It's hard to know how mainstream audiences are going to take a film like "American Beauty," which is much easier to admire than it is to like.

On one hand, this superb tragic comedy is so full of scathing, biting social observations that it's almost too painful to watch. But it also features what are surely the most watchable performances given by an ensemble cast in any film this year.

However, unless moviegoers get a taste for the movie's bitter wit — and realize that the title is not meant to be an ironic statement — this gem may go unappreciated by the masses, as did 1997's "The Ice Storm," a '70s-period drama that dealt with similar material in a more serious manner.

But to be honest, "American Beauty" makes that film look like a "Family Circus" comic strip. It takes the frank sexual material of this summer's gross-out comedy "American Pie" and gives it a serious, albeit satiric spin. In other words, you'll probably be chewing it over and thinking about certain situations and scenes for days, if not weeks.

Equally memorable is the lead performance by Kevin Spacey, whose understated work here may be the best of his already terrific career. He stars as Lester Burnham, a middle-aged advertising magazine writer whose life has lost its direction.

Not only is Lester on the verge of getting fired from his job, he and his real-estate agent wife, Carolyn (Annette Bening), have settled into a safe, loveless relationship. And his teenage daughter, Jane (Thora Birch), sees him as an object of scorn and derision.

Things change in a hurry for this nuclear family when Lester becomes smitten with Jane's best friend, the seemingly promiscuous cheerleader Angela (Mena Suvari, from "American Pie"). Soon he's experiencing a second "adolescence" of sorts, which includes a regimen of physical exercise and drug experimentation. Meanwhile, Carolyn begins flirting with her business rival, Buddy Kane (Peter Gallagher).

If that's not bad enough, Jane starts spending time with oddball, Peeping-Tom neighbor Ricky Fitts (Wes Bentley), who also keeps the Burnham household under constant surveillance with his handheld video camera and who has been supplying her father with his "stash."

It probably seems like there's enough material here for more than one movie, but somehow director Sam Mendes and screenwriter Alan Ball (who scripted TV's "Cybill" for several years) seem to give each character and story line enough time to blossom fully. And though the film's opening voice-over gives away the final fate of some of the characters, there's genuine suspense about what happens in the end.

Mendes, a veteran stage director making his feature-film debut, also steers the film skillfully through the waters that lie between the oceans of dark comedy and drama. And he coaxes beautifully nuanced performances from his cast — Bening never stoops to the easy, one-note characterization that might be expected from her part, and the younger actors (especially Bentley) really make the most of their screen time.

But the obvious star is Spacey, who makes Lester such a human character that you can't help sympathizing with him, despite the many embarrassing gestures on his part. His work here is surely worthy of an Oscar nomination — if not an outright win — come next year.

"American Beauty" is rated R for considerable profanity, as well as some sexually based humor and use of crude slang terms, simulated drug use (marijuana), simulated sex acts (some done for comic effect), male and female nudity, violent gunplay and gore.