Starting sometime in the sixties, probably under the influence of the great European and Japanese filmmakers, American film writers and directors began making films that needed a whole new kind of acting, a kind that depended on what you might call the absence of heroism. The icons were gone or going fast -- John Wayne, Gary Cooper, Cary Grant, Henry Fonda -- and now young, trained actors were available to flesh out their roles. These were actors who worked to embody the filmmaker's vision, who willingly, sometimes brilliantly, sublimated their own personas to serve the ends of the movies they made. Among the men, early on, we saw such unlikely leads as Elliot Gould and George Segal. Then it was Al Pacino and Robert DeNiro, and then the breathtaking Sean Penn.

And now we have Kevin Spacey, an actor with a presence, an aura to his work unlike almost anything seen before, as though he were landed here among us from another plane entirely. I think of the electricity generated by the young Jason Robards Jr., and the young Laurence Olivier as possible comparisons, but Spacey has taken over the worlds of both film and theatre simultaeously in a way that neither of them quite managed. And to put the conclusion first, when once Spacey has given us a role, a character, a human being, we cannot ever after imagine anyone else doing the part. That, I think, is his genius. He does not chew scenery, he does not distract from the overall power or force of a film, nor from the work of his fellow actors. But when he is on screen he commands our eyes and minds and hearts like no one else has ever done before.

Beginning with a minor role in 1992's "Glengarry Glen Ross" that led to his astounding Verbal Kint, the clubfooted antihero in 1995's "The Usual Suspects," he went on to play a Buckingham that gave us the core of that contradictory and betrayed character in Pacino's odd homage to himself, 1996's "Looking for Richard."

Then, with a brief stop to invest the character of Jack Vincennes, the good/bad cop in 1997's "L.A. Confidential," with more interest and compassion than was even written into the part, he moved on to Clint Eastwood's badly flawed "Midnight in the Garden of Good and Evil," where he played the gay Jim Williams absolutely straight, with enough flair and wit to almost, though not quite, save that film.

And now, after his triumph on stage as Hickey in the London production of "The Iceman Cometh," he is back in films with his ordinary, extraordinary Lester Burnham in "American Beauty." A first script by television writer Alan Ball, directed by the stage master but first-time film director Sam Mendes ("Cabaret," "The Blue Room" in London and New York), "American Beauty" is a comedy so dark it swallows us up like a black hole, a tragedy so filled with wit we giggle like children at a birthday party. It's the story of a year in Lester's life. He both narrates the film and plays in it. He is married to Carolyn, a perfect virago of a real estate agent (Annette Bening in a juicy role that shows her nice skill at comedy) and is the father of teenager Jane (Thora Birch) who's contemptuous of his pathetic attempts at being a good parent. But Lester comes unexpectedly into a life crisis when he's informed at work that his job as a media salesman is in jeopardy.

Many things happen at once, for Lester and for his family. He develops a crush on his daughter's high-school cheerleader friend Angela. Carolyn, who won't sleep with Lester, has an affair with another hotshot realtor. Young neighbor boy Ricky (Wes Bentley), who surreptitiously videotapes Jane at night, is also a wealthy dope dealer by day, and finds a good customer and friend in Lester. But Ricky's Marine colonel father (Chris Cooper) will trigger the film's denouement through his combination of blindness and rigid stupidity.

There's more, but what makes "American Beauty" work so well is that it is basically a novel set on the screen, with a richness of texture and an overlaying of emotion upon each incident, that deepens everything in it. Each character has been well defined in the writing, letting us in on their separate relationships with the other characters, so that we come to know them in their depths without the need for the artifice of a 'back story.' What plot there is grows out of those personalities and relationships; the film is character-driven, not plot-driven.

And here is where Spacey's genius shows best. He has the ability to invest a line of dialogue with every possible meaning -- its primary one, plus any contradictory, reinforcing, or even outlandish one -- simultaneously. At one point, a short sentence at the dinner table -- "Honey, don't interrupt me." -- becomes a shorthand statement of everything that's gone wrong with his life and their marriage. The overtones from that line keep ringing in our minds for the rest of the film.

As good as "American Beauty" is, it is not quite perfect. There's a clunkiness of structure as we near the finale, an unnecessary, even melodramatic acceleration of incident, that takes away from what could have been an even more powerful and resonant resolution. But we can't feel too badly about something so good it doesn't have to be perfect.