WRITER JIM Harrison, 42, newly successful, and wintering in Palm Beach, still was quite ready for a sudden return to the honky-tonk of Key West. He was looking for the old bad flash . . . walking home drunk on certain dark new moon spring nights when the music mixes with the smell of flowers and garbage and you get the feeling that the very next second might be the most important of your life. The lesson he'd learned over 12 years of fishing and carousing there was that the shrimper with the knife on Caroline Street and the mystery lady with the loose dark hair turning north off Southard can either kill you or cure you. Neither one will just pass by.

Harrison, whose new collection of novellas, "Legends of the Fall," has been hailed as work that might save traditional American outdoor toughness from the Hemingway blight of sentimentality, made the trip down in a Porsche Turbo 928. At the wheel was another Key West alumnus, Jimmy Buffett, the singer who turned the island into Margaritaville and then moved to Aspen. The Rolling Stones were on the tape deck and between them was plenty of drink and appetizers. They were telling stories about the old days and averaging 80 miles an hour on the Florida Turnpike. Word of their coming was out around the Chart Room and the Full Moon Saloon and the old friends were gathering.

These included Dink Bruce, son of Toby Bruce -- Hemingway's caretaker, factotum and drinking buddy from the '30s -- crusty old charterboat captain Bob Hall, who's in charge of Harrison's new $20,000 sportfisherman Revenge (named after the most violent of the novellas, which paid for it), an interchangeable flock of slinky dark barmaids, a knifemaker from northern Michigan where Harrison owns a small farm, various journalists, editors and publishers eager to make contact with this pair of living legends.

Nobody was disappointed. By 1 a.m., Harrison and Buffett, man and minstrel, were buying drinks fro everyone at two big tables in the Full Moon Saloon. The Porsche was sitting outside cooling off, but they were picking up speed. You understand that the Full Moon Saloon is the plastic unassuming roadhouse kind of place that tourists and the New York set now taking over Key West can't stand. If one walked in now, he'd se a raucous cluster of riffraff presided over by a short, powerful gat-toothed man with a Pancho Villa mustache, wandering walleye, and Apache chief facial structure. pThe tourist would do a quick U-turn, pretending to have forgotten something, never knowing how close he'd come to rubbing shoulders with a man that even the staid London Sunday Times allows has "immortality in him." And he probably wouldn't care . . . because Harrison's particular immoral qualities can be as violent, romantic and beyond the constraints of 9-to-5 civilization as a wicked two-day binge.

Jim Harrison sat there spinning tales at the Full Moon, unconnected stories joined together by a run of beer bottles and long-lost buddies: The time he caught a striped marlin on a fly rod in the Humboldt Current off Peru; why he loves hyenas and hates Erica Jong; the time his partner in Key West marginalia, novelist Tom McGuane, got hold of a Dupont Blaster's Manual and developed an exploding softball; the agony (including projectile vomiting and two days in a hot bath) of getting truly groined; and, he claims, the night he watched Bruce Jay Friedman throw Norman Mailer over a taxicab outside Elaine's. He and Buffett have interlocking riffs, like jazz musicians, looking at one another to signal takeover. Key West Sonata. On past closing time, into other locales, past sunrise, and Harrison found himself out in the street with a little bit of what he'd come for:

"I want to see the world not the way I want it to be but just the way it is . . . your flat perceptions . . . like coming out of the bar in bright neon, but the light is flat and metallic and they're digging up a sewer line and all the cars are covered with the grungy dust and I don't have any sunglasses and my head is sort of pounding . . . ."

Harrison loves the edgy, seedy existential sharpness of hangovers. The best hangover scene he ever wrote he remembers fondly, was set in the fly-blown Mexican border town of Agua Prieta . . . hundred-degree heat, air fouled by a copper smelter, a half-empty tequila bottle on the nightstand, white adobe cantinas and whorehouses out the window and a feeling that you're gone more than one step over the line. He wants to develop it into a whole screenplay: "Mexico has always fascinated me. It's just not very ambiguous. The nights are dark and you can resolve your vices on a very immediate basis without going on making smart chitchat about health foods."

He was nursing a fine hangover at about 5 p.m. on the next day in Key West, with Buffett still asleep upstairs and Captain Bob steaming fresh Gulf shrimp and lobster in beer as a prelude to the second evening. A lot of stretching and groaning, pouring of beer over ice cubes and searching for Tylenol . . . Captain Bob fondly remembering many past indiscretions almost in the manner of an old high school athletic coach with his former stars. The High Boogie as athletic event. You could see it all beginning to pick up speed again and are not surprised to learn from Harrison's secretary that the hours of his writing day are not too much different from his drinking day; up in early afternoon, a kind of beer breakfast of writing until 6, break for dinner and back at it, driving through into the small hours and sometimes stringing it out till dawn.

Soon the group was back on Duval Street, striding along pretty high and wide like conquering heroes down to Captain Tony's bar, the original Hemingway hangout (which Harrison and Buffett agree is the one real tourist place that has managed to "preserve its integrity"). Buffett up on the stage singing "A Pirate Looks at Forty" while the tourists rub their eyes in disbelief and Harrison standing at the bar saying hi to Captain Tony and the usual parade of long-lost buddies . . . the progress swelling in a second wave that washes way up again into the late morning, when Harrison and Buffett caught each other's eye and fled the city in a Learjet back to Palm Beach. Harrison's secretary drove back with the Porsche.

The three novellas in "Legends of the Fall," two of which appeared in Esquire magazine last year and the year before (the title one being the longest work of fiction every published there) would seem to be the most essentially straightforward chronicles of life beyond the pale to be told in quite a while. A strong man is driven to revenge. A strong man is driven to outlawry. A strong man is driven to seek anonymity as a cook. They are told in a matter of fact, distant way reminiscent of 19th-century chronicles or those of Isak Dinesen: "Late in October in 1914 three brothers rode from Choteau, Montana, to Calgary in Alberta to enlist in the Great War (the U.S. did not enter until 1917)."

And: "Nordstrom had taken to dancing alone."

And: "You could not tell if you were a bird descending (and there was a bird descending, a vulture) if the naked man was dead or alive."

The women in all of them are fateful, sometimes fatal, adjuncts to the strong men. There is almost a mystical faith and fascination in the efficacy of violence asd nature's own solution. The three of them were written in about three months of 18-hour days and earned Harrison somewhere in the middle six figures in publishing and screen rights, and various spinoffs.

Before "Legends," he had averaged a scanty $10,000 a year writing award-winning macho poetry (five volumes) and three other novels which had never quite taken off. There was a lot of diffuse, barroom writing in them and sometimes the reader felt he was trapped for the evening next to a vicious whimsical drunk. But there were also brilliant original sections that showed in fact that the natural world might be at its most interesting when seen through the rueful perilous hangover of late 20th-century burnout.

So it seemed to actor Jack Nicholson, who staked Harrison to $15,000 while he wrote the novellas, and to Ray Cave, who arranged a contributing editorship for him at Sports Illustrated while he was still struggling.

Now in the truck Cochran had the wit to recognize he was in the right frame of mind for what he had set out to do: he had few thoughts, only a purpose; the thoughts were so few that they would not interfere with his mission which clearly was to kill Tibey and to get Miryea back if she was alive.. He had been so empty of thought the world had begun, in an odd way, to delight him again because there was nothing in his mind to interfere with the beauty of the valley or, for that matter, the energetic ugliness of the contemporary world he was entering. -- From "Revenge"

On the dust cover of "Legends of the Fall" is a picture of Harrison that actually makes him look more hungover and potentially violent than even his heroes. His blind walleye (gouged by a girl playmate at the age of 5) is screwed up tight in the heavy dark face. The cowcatcher chin is covered with stubble and the Hawaiian shirt hangs open over a brawler's chest. You can't see the gat teeth, which is just as well because they give him a kind of a loony look that offsets the threat and go better with the bib overalls and weird caps he has affected in former less erious dust covers.

"I have never been mugged," Harrison likes to boast.

As a real person, though, (opposed to a figment of his own imagination or his publisher's) Harrison is actually more concerned with writing than he is with fighting, drinking, hunting, fishing. He has an MA in comparative literature, has put in time as a professor of English at the State University in New York in Stony Brook, and has corresponded for years with figures like poet Denise Levertov and novelist Peter Matheissen. He has read widely and deeply -- sometimes guided by a brother who is a librarian at Yale -- in surprising areas like marine biology and late 19th-century Western American history, and has an almost wide-eyed respect for education. In unguarded moments he will admit to being "totally overwhelmed by the primacy of art," or being "irrationally preoccupied with ideas all my life."

He is also one of those people who never totally loses track . . . even lying on his back like a beached whale at 5 a.m., still good for a pronouncement or two: "Oddly enough, I've never not known how many drinks I've had. Phil Clark [Buffett's model for 'A Pirate Looks at Forty'] said an irritating thing about six years ago in Key West. 'Harrison, you know the difference between you and everybody else is that you never let go.' And this is when we were all being crazy. It upset me for a bit because I thought My God he's right."

Harrison had roughly the same kind of upper Michigan childhood as Hemingway, too: son of a county agricultural agent who carefully taught him birdshooting, fly fishing and how to handle himself in a bar. His father learned from his father, a logger who once cleaned out a bar on crutches with a broken leg for being called a cripple. Harrison says there is a Scandinavian capacity for berserking from his mother's side.

On violence: "Some people told me it was revolting when I had Tristan [the hero of 'Legends'] kill that guy with a pitchfork. I said well if you're in a stable and the only thing you have is a fork, that's what you would use. A fork. The worst farm murders often involve forks. But that's the nature of growing up in an area where your dad says something to you, and he's a sort of a wise almost elegant person, says when you sit in a bar never curl your feet under the rungs of a barstool in case you're sucker punched. The most interesting thing about violence is it's matter-of-fact nature." He talks about how Cochran, the hero of "Revenge," guts a man from crotch to chest, in a toilet checks himself in the mirror for blood, grins, and leaves "unhurriedly." Also how he himself was standing in a men's room once and watched someone stab someone else through the face with an icepick. . . .

The straight Michigan upbringing involved a respect for permanence and place. He's been married 20 years to a childhood sweetheart (they have two daughters, 19 and 9), and the little farm they now own is only 70 miles from where he was born. There is the Hemingway reverence for "particular knowledge": exactly how the fish move through certain channels, how a karate champion just manages to ruffle his trainer's hair without killing him, how a race-car driver corrrects a drift at 200 miles an hour, even how an oil lease is negotiated. What he hates is politics: "The art of compromise, imprecision and covering ass."

Harrison's third novel, "A Good Day to Die," says a lot of what there is to say about his idea of friendship. Two strong men meet in Sloppy Joes Bar in Key West, get drunk and then hungover, and decided they like each other engouth to try to blow a nonexistent dam together. The nonexistent dam is thousands of miles away in the Grand Canyon. They grab a woman and start driving. The novel is deicated to Dan Gerber, another spoke in the Key West wheel of Harrison, McGuane, Buffett: et al, who is an heir to the Gerber Baby Food fortune, a former race-car driver, novelist and poet. A lot of Harrison's friends seem to be rich, or at least comfortably off, as are a lot of his heroes, he says, for the simple reason that the most interesting preoccupations require free time and don't come cheaply.

One warm still day in a deep tidal creek he hooked a tarpon and was shocked as it hurtled out of the water near the boat, twisting its big silver body and its gill plates rattling before it broke off. That day he thought he counted a thousands shades of turquoise in the water. He had become a water, wind, and cloud watcher in addition to being a cook. Late at night he danced to a transistor radio. -- From "The Man Who Gave Up His Name"

But not . . . fame, fortune and Palm Beach. The mind boggles with a vision of Harrison in tennis whites telling a genteel anecdote or two to the blue-haired set around the Bath and Tennis Club pool.

His wife Linda, tall, thin and dark with a pair of what are probably the heaviest eyelids in Palm Beach, says it's a one-time shot. She looks bored. h"We only came here because of Jim's fishsing friend anyway," she says.

But Harrison seems to kind of enjoy the shift:

"I mean basically I think you need more mad dogs and fewer streetlamps and this place confirms it," he says from beside his rented swimming pool. "What an unbelievable geek show. When you go into Hobe Sound you know your car is beieng tracked by a form of radar that times your passage through, and whether you're doing anything eccentric. It's just that thing about people thinking they're going to be mugged. You know. You can learn a lot about it here."

The shift actually seems to complement the book he's working on now, which is a long way from the hard, compressed action of "Legends of the Fall." It's comic ("because that's the only book I can write now"), about a private detective in an area of northern Michigan where there is no crime whatsoever. A dada private detective who is deeply concerned about "everything," including the president's dog and whose wife is unfaithful.

But there is bound to be a touch in this book (as there is in most everything he writes) of the enduring fantasy inspired 15 years ago by the tragic death of his father and sister in a car accident:

If my sister hadn't died in an auto wreck

And had been taken by the injuns

I would have something to do:

Go into the mountains and get her back.

Or, as he tells it: "I'm always having a man in desperate straits trying to help seombody else out with no apparent success because nobody can be helped by anybody." Which gives you a fair idea of how it fels to wake up hung-over in Agua Prieta.