October 19, 1990 | “Nobody knows anybody -- not all that well!'' These are words to live by, voiced repeatedly -- sometimes angrily, sometimes almost sadly -- as the personal credo of Tom Reagan (Gabriel Byrne), a man who knows whereof he speaks. And audiences that follow him through the labyrinthine plot twists and explosive shootouts of Miller's Crossing will have to agree. Certainly, no one -- maybe not even Tom Reagan himself -- can presume he knows Tom, or why he does what he does.

Tom serves as the tantalizingly ambiguous heart of darkness in Miller's Crossing, a movie that infuses the clichés and archetypes of '30s gangster movies with an edge of passion and a hint of put-on. It comes to us from Joel and Ethan Coen, the aggressively gifted filmmakers who made us sweat with Blood Simple, then made us howl with Raising Arizona. Miller's Crossing is their most ambitious and accomplished work to date, being a seamless blend of artifice and artistry that, in the end, is one of the most affecting love stories of recent years. No kidding.

Filmed on location in New Orleans, but set in some unnamed Eastern city of 1929, Miller's Crossing is, on its simplest level, a tale of gang war. Tom is the brains behind the considerable muscle of Leo (Albert Finney), the Irish kingpin who runs the local rackets, pays off the police and politicians, and generally runs the city as his private kingdom. But there is an impatient pretender to the throne: Johnny Caspar (Jon Polito), an Italian mobster who places great value on friendship, loyalty and ethics -- or, as he says it, ''et-tics'' -- when those attributes serve his purposes.

As Johnny sees it, it's highly “unet-tical” for a bookie to leak word that a fight has been fixed. ''If you can't trust a fix,'' he complains to Leo, ''who can you trust?'' Bernie Bernbaum (John Turturro), a recklessly untrustworthy bookie, has been costing Johnny a great deal of money. ''So you want to kill him?'' asks Tom. ''For starters,'' says Eddie Dane (J.E. Freeman), Johnny's right-hand thug.

But Leo refuses to lift his protection of Bernie. For one thing, he doesn't like Johnny's disrespectful attitude. For another, more important thing, he's deep into an affair with Bernie's femme fatale sister, Verna (Marcia Gay Harden). Tom thinks protecting Bernie is an unwise move, and says as much to Leo. He dearly wants to change Leo's mind, even while he seeks a way to avoid mentioning that he, too, is seeing a lot of Verna these days.

At first, it seems Tom and Verna are made for each other. ''Intimidating helpless women is part of what I do,'' says Tom, doing his best to frighten Verna. ''Then go find one and intimidate her,'' snaps Verna, who isn't the least bit frightened. Then, just to make sure he gets the message, she socks him, and he flies across the room. Still, Verna is the first to admit it: ''The two of us are bad enough to deserve each other.''

So maybe Tom is at least partly motivated by jealousy when he finally tells Leo about his relationship with Verna. And maybe Tom is driven by revenge when, after Leo beats the hell out of him and throws him out of his gang, Tom joins Johnny's organization. And maybe Tom is going to settle things by taking care of Bernie once and for all.

And then again, maybe not.

One moment, Tom seems like a Machiavellian genius. The next moment, he seems like a desperate small-timer who's not nearly as clever as he thinks. He's a punching bag for just about anyone willing to lift a fist. He's a vicious schemer who is just as cold and remorseless as the killers he manipulates. Tom fires a gun in dead earnest only once, but that's more than enough. Someone begs him to ''look in your heart'' on two different occasions, and that's one time too many. Why? As Tom puts it, ''What heart?''

Gabriel Byrne is marvelously subtle and rivetingly mysterious as Tom, a man who protests far too much when he's accused of feeling anything like a conventional emotion. When he speaks of a dream, in which the wind blows his hat away, Verna is quick with an interpretation: You chased after the hat, and you caught it, but it turned into something else, right? Not at all, Tom insists. The hat blew off, and that was the end of it, because ''there's nothing sillier than a man chasing a hat.'' Unless, of course, it's a man risking everything to protect someone he loves.

Joel and Ethan Coen have written a terrific screenplay that, in addition to being witty, intricate and constantly surprising, is rich in snappy patter and colorful slang. (''What's the rumpus?'' is the standard greeting for rivals, friends and lovers.) Miller's Crossing, which Joel directed, takes the ''dirty town'' plot of Dashiell Hammett's classic Red Harvest, but fills it with characters straight out of Damon Runyon, and peppers it with the shocking violence of The Godfather.

In some ways, the film is as stark and stylized as a Bertolt Brecht anti-drama. (Except for gangsters and cops, the streets are almost entirely empty.) But the production values are darkly lush and the action sequences, even the most violent shootout, are jarringly juxtaposed with the warm nostalgia of Irish ballads. Like Tom, the movie contradicts itself, and is all the more fascinating for doing so.

The acting is flawless. Albert Finney -- a last-minute replacement for the late Trey Wilson -- brings unexpected poignancy to his portrayal of an aging, lovesick mob boss, and has the stellar presence to remain an imposing figure during the long periods when he is not on camera. John Turturro is a sweaty, sneaky, altogether credible weasel as Bernie. Jon Polito is as amusingly venal as J.E. Freeman is seriously menacing. Marcia Gay Harden is, hands down, the best hard-boiled, wisecracking dame to hit the screen in years.

Most important, there is Gabriel Byrne as Tom, a seemingly self-destructive fellow -- he gambles to excess, and drinks even more excessively -- who nonetheless can take anything that anyone can dish out. The only time Tom ever really loses his cool is when he fears he cannot talk his way out of a violent demise. In the end, though, you know -- you just know -- that he would rather take a bullet before he ever would let anyone know him all that well.