NEW ORLEANS, an unlikely collision of technology and garlic butter, sits in a loop of the Mississippi River that at one point flows north. The sun can rise and set on the same bank, and if you can figure that out, you belong there.

N'Awlins (never "New Or-leans") is irrational, hedonistic, violent, corrupt, snobbish and, if you can stand it, irresistible. It teeters on the literal and Biblical brink of inundation. A.J. Liebling drew a parallel between it and the Mediteranean littoral, but Liebling had it wrong. New Orleans is really the vestigial link between the Deep South and the Mosquito Coast, the United States' most venerable banana republic, a bayou ziggurat supported by old oyster shells and the untrammelled urges of the Piltdown Man.

I arrived in 1965 as a cub reporter for the Times-Picayune, a few hours before a hurricane carpeted the city with broken glass, pushed big oaks down across trolley lines and deposited alligators in suburban geranium beds. Because I was the only reporter foolish enough to go to work the next morning, the first newspaper story I ever wrote, about a city of which I was ignorant, appeared on page one, with a by-line.

I became a police reporter; I learned more about New Orleans than I cared to know. For me the See NEW ORLEANS, Page 5, Col. 1 Dejans Olympia Brass Band in front of St. Louis Cathedral New Orleans NEW ORLEANS, From Page 1 city will always be touched with early promise, and with disaster: the sound of carillon bells, the bark of a pistol, the fragrance of oleander and sweet olive, the sight of blood freckling old flagstones, and, of course, food--fried oysters, red beans and rice, grillades and grits, shrimp Creole . . . but we'll get to that. (You always do, in New Orleans.)

I had heard that the city was French, and genteel.

In fact, it was rougher than Marseilles, and mightily stocked with Italians, Irish, Africans, Americans (a separate immigrant group), Hispanics, Greeks, Germans, Yugoslavs, Filipinos, Lebanese, Canary Islanders, Cajuns, Chinese Presbyterians and dozens of hybrids, as well as the descendants of French and Spanish settlers. And they all brought their mothers' recipes.

Food is not only an index of the city's chaotic ethnicity; it is also the primary recreation. If you don't like to eat--and drink--then forget it. What harmony exists among the myriad social distinctions is dependent mostly upon satisfied appetites. No brothel can compete with the crab houses up on poles in Lake Pontchartrain, or the dozens of salons of gastronomic eroticism.

Sitting in the middle of the cultural stewpot is a unique phenomenon known as the "y'at," a name derived from their salutation: "Where y'at?", meaning "How are you?" The familiar version is, "Where y'at, ya mother?" The accent is identified with the poorer neighborhoods, the Ninth Ward and the Irish Channel, closer to the "dems" and "doses" of Brooklyn than the dulcet cadences of the South, to which the city bears little resemblance.

A friend of mine, an Anglo-Saxon Protestant native with the sympathies of a boogaloo Louis XIV, first explained how y'ats are identified, and I pass the information along. "At the Saints' games the y'ats are the ones who buy the Nacho cheese dip. When a hurricane's coming, they drive their love vans out to Schwegmann's (a huge grocery-liquor store) and load up on Dixie beer and Zatarain's Crab Boil. Then they drive up onto the levee, and howl into the wind."

Perhaps the most famous y'at was the former mayor and friend of Huey Long, Robert S. Maestri. He made a fortune selling and re-selling beds to whorehouses that had been confiscated in police raids, what one observer called "the original model of perpetual motion."

Y'ats are easily recognized on Mardi Gras by the stepladders, folding chairs and coolers with which they line the parade routes. Each y'at constructs a gustatory fortress and hunkers down inside with family and allies, occasionally disengaging a hand from his plastic tankard to snag a "throw" hurled from a passing float. By midday on Fat Tuesday (this year, Feb. 15) about half a million y'ats line Canal Street, all clambering for dubloons and plastic beads.

Mardi Gras is a muscular business. It is not the worst time to visit the city (the worst time is August, when the crawfish have all been eaten, and the streets stick to your shoes), but it's certainly not the best time. People start drinking shortly after dawn, and the casualties are staggering. On my first Mardi Gras I saw a famous clarinetist so drunk at 9:30 in the morning that he had to be steered like a locomotive down the middle of Magazine Street. (He was later hit in the head with a brick, which apparently didn't faze him.)

Rex, king of Carnival, makes an official pit stop on Canal Street at the Boston Club, the social pinnacle of New Orleans that is surrounded by a nimbus of blinding tradition. It is a measure of the founder's self-assurance that in 1841 they named their club after a card game that happened to correspond to the name of a large Yankee city. Then as now, no Jews, blacks, or women need apply. Dominated by the descendants of mostly Anglo-Saxon Protestant businessmen, the Boston Club practices a kind of Louisiana Shintoism where the worship of ancestry surpasses even the worship of money.

"They are totally involved in Carnival," says one who insisted upon anonymity. "Mardi Gras has a stranglehold on this city, socially and economically. The clubs, the important Krewe"--clubs staging elaborate parades --"and the young women's debuts are all part of the same year-round process. Planning for next year's season--picking the queens, planning the tableau, picking the material, arranging diners and soliciting funds--begins practically on Ash Wednesday."

Fortunately most people are not bound by these strictures. The most common emotion among the populace is food lust, instantly recognizable and almost as quickly satisfied. A y'at favorite is a Ferdi sandwich, found at Mother's, a combination of hot roast beef and ham on French bread soaked in meat drippings, garnished with pickles and spread with mustard and mayonnaise. (It has been suggested that Southerners behave erratically because we all suffer from mayonnaise poisoning.) From Mother's the fare climbs steeply, from Buster Holmes to Mandina's to Galatoire's to LeRuth's across the river in Algiers.

On Bourbon Street you can buy a cup of beer in Woolworth's, and a Lucky Dog--a south Louisiana hot dog served with chopped onions.. Head downtown past T-shirt vendors, praline shops, a voodoo emporium, strip clubs offering glimpses of floodlit flesh in the afternoon, a Takee-Outee ("30 Second Service"). Here the smells are all-American: hot grease, booze, popcorn and cannabis.

The streets you cross are alternately named for saints and sinners--St. Peter and Orleans, St. Anne and Dumaine. Follow one of them toward the river, and the French Market on Decatur Street. Here the names are mostly Italian: Ruggiero, Cuccia, Brocato, Tusa. The Italians pushed the Irish off the docks in the late nineteenth century, and kept cows on the landings in the elegant old Pontalba apartment buildings on Jackson Square. They gunned down the first Irish police chief; the word Mafia came into common usage during the trial. It was the name of just one secret society, but short enough to fit the front pages of the tabloids.

The name most often linked nowadays with organized crime is that of Carlos Marcello, in neighboring Jefferson Parish. Marcello may be the only person to ever have evoked the Fifth Amendment when asked whom he sold tomatoes to.

My friend, when asked about organized crime, says, "Actually it's disorganized crime. The only Mob activities involving the locals are gambling and prostitution, and those aren't considered crimes in south Louisiana."

The Central Grocery, next to the French Market, is the provisional oasis of the lower Mississippi. There you will be stricken with the smells of Genoa salami, provoloni and antipasto, all ingredients of the notorious muffuletta sandwich on round loaves. Stacked in the windows are cans of green peppercorns, lupini beans, Calamato olives, a dozen brands of olive oil, fried bean curd, adabo seasoning, carob molasses, vine leaves, Hungarian paprika, lychees, coconut oil, paella and roses in heavy syrup; bottles of Pickapeppa sauce, Tabasco and Evangeline green hot sauce, mango pickle, creamed quince, pasteles de yuca and Taiwanese snails; tins of cock oysters, shrimp and conch.

Inside, shoppers navigate around sacks of semolina, corn flour, red lentils, brown rice and Chinese pine nuts. They push aside old sliding glass doors to get at the bins of pasta--rigatoni, mafalda, cavatuni, bucatini; they pluck packages of Creole rice, jambalaya and papers for wrapping tamales from the shelves, along with whole garlics, jalapeno jelly, candied chickpeas and licorice pastels.

The Italians made a major contribution to New Orleans cuisine through the liberal use of oregano, basil, rosemary and garlic, and the traditional tomato sauce. (Most sauces in south Louisiana begin with a roux.) New Orleans cooking is a combination of Creole--itself a combination of French, Spanish, India Indian, African and southern American--and Italian, Cajun, Chinese, Latino, Greek, and a few other strands.

One noted receptacle of local spoon lore is Paul Prudhomme, from Opelousas, who owns a popular restaurant dedicated to serving genuine New Orleans fare in all its diversity. It is called K-Paul's, on Chartres (that's Charters) Street, behind the old Opera House. While head chef at Commander's Palace, Prudhomme devised a dish he called Shrimp Chippewa, after Chippewa Street in the Irish Channel. That simple combination of sauteed shrimp, garlic, shallots and mushrooms, served with hunks of French bread, summed up the culinary diversity of New Orleans, being basically French but devised by a Cajun, named after America Indians in honor of the Irish.

New Orleans happens to contain what I modestly call the best bar in the world. It is the Napolean House, just down the street, built by a Frenchman as a retreat for the liberated Bonaparte--one more failed New Orleans conspiracy. For most of this century it has been owned by a family with the grand old Gallic name of Impastato. Oil paintings hang askew on yellowing walls; Bach issues from dusty speakers.

In warm weather big doors are thrown open to the street, and the wooden blades of overhead fans gently stir the aromatic mix of the French Quarter: the smells of roasting coffee, muddy Mississippi, spilled beer and the combined exhaust from the kitchen fans of Antoine's, Brennan's, K-Paul's, Tortorici's and Castillo's. Order a Dixie, or a Sazarac, and watch the rich variety of New Orleans--including, yes, tourists--drift through the Lautrecian incandescence.