BY LARRY CARROLL | It's a well-known fact among cinephiles that Orson Welles and Herman Mankiewicz referred to Citizen Kane as The American while they were in the process of writing the film, a name with which it was almost released. The co-authors considered the title because they saw the first half of Kane's life as the embodiment of the American dream. Building yourself a castle and becoming a newspaper mogul, however, seems more fantasy than realistic goal-setting to the average U.S. citizen. Perhaps then The American moniker should have been revived for About Schmidt, a mordant tale of someone who has achieved all that a man should, only to realize that it has become his nightmare.

Jack Nicholson is Warren Schmidt, an actuary for the Woodmen of the World Insurance Company, retiring from a lifetime of service. In a brilliantly appropriate introduction to the man, we see Warren sitting at his desk in a nearly empty office, watching the last seconds of his working life tick away. Warren and his wife Helen (June Squibb, Meet Joe Black) then attend his retirement party, where co-workers, friends and other well-wishers surround them. Warren is beginning the greatest time in life, the time that each schlub who heads off to work with his head down everyday dreams of - retirement. He has a beautiful house, a wife of 42 years, a daughter he adores, and a 35-foot motor home with which he plans to see the country.

But something's not right. Unable to enjoy his party, he says he's going to the restroom and instead sneaks to the adjoining bar for a drink in solitude. He makes secret trips to Dairy Queen so he can get himself a Blizzard for a treat (ordering a medium, presumably because he doesn't think himself worthy of too much a reward). In a hilariously bitter voiceover, he recounts all the mean things that his wife has done to him over the years (including a demand that he sit down whenever he pees). As a happy man, Warren is completely miserable.

When Helen suddenly passes away, Warren begins a journey that will see his existence peeled away, layer by layer, until he is reduced to his bare essence. He gets in his motor home intending to go to his daughter Jeannie (Hope Davis, Mumford) and spend some quality time , but she harbors some ill will towards her emotionally distant father and tells him not to come. Jeannie is in the process of planning her wedding to a mulletted waterbed salesman named Randall (Dermot Mulroney, My Best Friend's Wedding), and has enough on her mind at the moment.

Warren has never considered Randall worthy of his daughter, who he deifies as if she were still a ten year old angel, and he is scared to death of dealing with the issues that have suddenly been thrown in his face - his loneliness, guilt over a lack of grief for his wife, his obsolescence from the working world - so he takes on a new mission: to open his daughter's eyes and convince her to stop the marriage from going forward.

Just as Kane reconstructed a man's life through the eyes of the people who knew him, About Schmidt does the same by showing us how little a man knows about himself. Warren drives around somewhat aimlessly, having memorable encounters with an American Indian convenience store worker, a married couple who seem too nice to be real, and the tire store employee who works where the house that Warren was born in once stood. The film revels in the beauty of a man finally living his life - watching the stars, stopping at tourist traps, not having anything planned or thought out - and these are the best moments.

Director Alexander Payne (Election) and his screenplay collaborator Jim Taylor have not only created a memorable lead character, but they have also invented what might be the greatest performance by a nonentity in the history of film. I am referring to Ndugu Umbo, a six-year-old Tanzanian orphan, who Warren adopts after watching one of those "Feed the Children" television commercials you see in the middle of the night. Throughout his journey, Warren details his adventures and thoughts with the boy through sincere, hilarious, and frequently touching letters. The fact that Warren trusts this company, that he would blindly say all these personal things about himself and genuinely think that Ndugu is actually reading them, speaks volumes about the man. It's a brilliant narrative device - one that makes Payne's job much easier as he tries to convey the thoughts and emotions of a man alone.

By the time that Warren finally gets to his daughter, it's his own eyes that have been opened quite a bit, and the film has firmly taken hold of you. Payne is a master at capturing the spirited simplicity of flyover territory. His characters are always genuine, shown warts and all, and just eccentric enough to be interesting. His camerawork is similarly subtle and fully considered. Particularly memorable are the still establishing shots of Warren's office building, the images during Schmidt's visit to a frontier museum, and the Hummel statues that seem to dance on top of Schmidt's Winnebago as he drives away with them on the roof.

Payne has created a beautiful canvas, and Nicholson proves once again that he's the best brush in the business. All those exaggerated facial expressions the actor is famous for, along with the trademark bombast and (there's no other word for it) cool demeanor are flipped over, inverted, and channeled instead as slow, minimalist subtlety. Nicholson gets downright ugly in this film, walking around in his pajamas, putting his hair in a pathetic comb-over, acting spoiled and sad and pathetic - but always human. It all builds to what might be the best final scene in a movie this year, a final moment of release. Nicholson's amazing career will still fascinate people a hundred years from now - and this is one of the performances they'll be looking at.

The supporting actors will make an impression on you as well. Kathy Bates, as Randall's sexually liberated mother, is especially a treat. Every time the woman is on screen she takes a movie overflowing with life and somehow manages to squeeze a little bit more in. Seeing the actress go toe-to-toe with Nicholson (most memorably in a hot-tub scene) is like watching two great boxers in the ring - as they dance around and feel each other out, they bring out the best in one another. Bates, already an Academy Award winner, may just get herself another nomination from her superior work here.

Hope Davis, as always, is solid as a rock and so gracefully plain that you'd swear you're going to bump into her next time you're at the supermarket. Mulroney is clearly inspired by those around him, meanwhile, and becomes practically unrecognizable for what is the best performance of his career. Not to be left out, however is Howard Hesseman; Dr. Johnny Fever has been too absent from pop culture over the last few years, and it's good to see him back. I joke by making reference to his old gig, of course, but few actors can play intelligent, sarcastic, dry wit the way that Hesseman always could. His banter with Bates is terrific - the two of them should get their own movie.

About Schmidt is a movie that comes along only once every few years. It's a film about a real man who has real flaws. It's a film about adults, made for adults. It teaches us a great deal about ourselves, our fathers and spouses and children, and about the dreams that all us Americans share.

GRADE: A