IN "AMERICAN Beauty," 42-year-old Lester Burnham informs us that in less than a year he'll be dead.

How could Lester (Kevin Spacey), the apparently successful husband of lovely Carolyn (Annette Bening) and the proud father of teenage daughter Jane (Thora Birch), get into such a fix? This overriding question gets its answer. But only after we've experienced one of the year's finest pictures.

By turns hilarious, painful and brutally frank, "American Beauty" gets America right where it lives: in the cookie-cutter paradise of green lawns, manicured roses and automatic garage doors known as suburbia. And no one brings this familiar place closer to home than Spacey, with a performance that practically glows with vulnerability.

Poor old Lester would be climbing the walls if he had the energy. Frustrated and defeated by everything, he slouches through life with barely a flicker in his eyes.

It's hardly surprising. His wife would rather fantasize about her manicured roses and real estate ambitions than get conjugal. His sullen daughter openly sneers at his ham-fisted attempts to communicate. And his job as an advertising representative is a soulless ritual.

For comfort, Lester resorts to sexual relief in the shower and, on one ultimately comical occasion, in bed next to his wife. As far as Lester's concerned, he's already dead. That is, until a cheerleader's sinuous legs, lustrous hair and killer-blue eyes render him breathless.

It isn't just that Angela (Mena Suvari) is human steam in a skirt. Or that she makes her seductive intentions toward him real clear. Or that she happens to be Jane's best friend. It's that she just jump-started a stalled motor. Lester dusts off the barbells in the garage and starts a jogging program.

Angela isn't Lester's only source of inspiration. After befriending 17-year-old Ricky (Wes Bentley), Jane's strange classmate who sells killer weed and doesn't care about his part-time waiting job, Lester gets positively radical.

"I think you just became my personal hero," says Lester, after witnessing Ricky casually quit when his boss threatens to fire him.

Lester quits his job, starts getting stoned the way he used to in the 1970s and puts the women in his family on notice: He's back. From now on, he's doing whatever he likes, when he likes. To hell with them and the mortgage.

No one takes this lying down. While Lester gets fit, smokes grass and experiences heady visions of Angela in rose petals, Carolyn changes her direction. She has always been obsessed with wealthy real-estate king, Buddy Kane (Peter Gallagher), whose financial success she craves. Now it's time to make a play for the competition -- literally.

Meanwhile, Jane becomes involved with Ricky, a dead ringer for the young Norman Bates, who makes videos of anything -- and anyone -- that interests him, and suffers physical abuse from his disapproving, machismo father, Col. Fitts (Chris Cooper).

Alan Ball's extraordinary script -- beyond the creation of Lester -- takes such worn stereotypes as the militaristic dad, the sulky teen and the Martha-Stewart-nightmare wife and pumps them with life.

Legendary cinematographer Conrad L. Hall lights this cul-de-sac world with vivid, luscious tones -- particularly when he's filming Lester's glorious, petal-happy fantasies. And British director Sam Mendes, who directed the London and Broadway productions of "Cabaret," begets an outstanding array of performances.

Not that anyone needs coaxing: The actors are uniformly good. Bening wires her role with such high-voltage archness and vitality, we'd swear we like her; and Cooper finds deft grace notes in that spit-and-polish character. But if "American Beauty" belongs to any actor, it should be considered Spacey's exclusive property. His portrayal of the beleaguered suburban male of the species is so achingly tender, our connection with him extends achingly beyond the grave.

AMERICAN BEAUTY (R, 118 minutes) -- Contains sex scenes, nudity, masturbation, obscenity and gunshot violence. Area theaters.