At the end of her first day at the remote mountain camp she was to call Karisoke, Dian Fossey watched her European guide disappear down the mud track and was left alone with her new African staff. As she gazed out over the crumpled green landscape to the misty checkerboard of farm land far below, she was startled by a voice. It was the woodcutter asking, in Swahili, "Do you want water?"

"I was nervous and I misunderstood him," she remembered years later. "I thought he had said, 'Do you want me to kill you?' I ran into my tent and zipped it up and didn't come out for hours."

Fossey always laughed when she told the story years later. That day in late 1967 was one of the few times she was to show fear, at least in public. And from the very beginning of her long sojourn at Karisoke Research Centre, 10,000 feet high in the Virunga volcanoes of Central Africa, she treated the plight of the rare and endangered mountain gorilla like a private range war.

It is that war -- its skirmishes with poachers in forest ambushes, its arrests and interrogations, black magic and passion -- that gives her murder by repeated blows from a panga knife sometime during the night of Dec. 26 the terrible and grim inevitability of tragedy. She was 53, and had studied the gorilla in Rwanda's Parc des Volcans for 18 years.

The murderer has not been found, but those who saw the condition of her ransacked cottage -- the crawl space neatly cut through her bedroom wall, the almost methodical six blows to the head, the valuables that were left untouched -- say the crime was planned with some care.

There are those who are convinced Fossey was slain by a poacher; others who insist that the answers lie elsewhere, that a simple forest poacher could never have pulled it off without help from someone else. Others note that Fossey had been dogging poachers for more than a decade. Why would a poacher strike now?

Fossey's battle to save the rare mountain gorilla, whose only habitat is a kidney-shaped patch of mountain forest shared by Rwanda, Zaire and Uganda, was waged with ruthlessness and courage, wit and questionable tactics. She pursued it long after she had ceased scientific research, long after her vigilante methods had been censured by some, long after the Rwandan government had begun to accept, albeit slowly,the need to save the mountain gorilla and its home.

Like a general convinced that compromise means defeat, she kept herself aloof from rival conservation groups, Johnny-come-latelys she said, that had adopted a more cooperative attitude toward the Rwandan government and practiced "theoretical conservation" that failed to halt the poaching that had halved the population of Gorilla gorilla beringei in less than two decades.

Caught in the uneasy warp between the rich and romantic world of western conservationism and Third World poverty, she was imperious and kind, sentimental and ruthless, capable of great kindnesses as well as a single-mindedness that, to some, seemed more like misanthropy.

"I used to have sympathy for the old Watutsi shepherds who used to take their cattle up there to the forest in dry season," remembers a close friend. "Dian showed up and the first thing she said was, 'We have to get rid of the cattle.'

"Now those old shepherds knew their cattle would die if they didn't get pasturage. When I found out Dian was taking away the shepherd's baskets of food I thought, 'Oh, how cruel.' But she had an idea, and if it weren't for her there wouldn't be any gorillas left in the Virungas."

Not long after that, still alarmed at the encroachment of the long-horned Achole cattle that were mowing down gorilla vegetation and pushing back the edge of the ever-diminishing rain forest, Fossey took her pistol and shot 30 head at close range. It pained her to do it, she said, but she felt she had no choice. "There are a lot of people who never forgave her for killing the cows," said Kelly Stewart, a former Karisoke researcher.

Later still her battle against local poachers began in earnest, a battle intensified by the slaughter of several gorillas in late 1977 and 1978.

After her death, friends would say Dian Fossey was always most comfortable with animals and children. She had said that as a young woman she had most wanted to be a wife and mother.

"She had so much love to give," said Ian Redmond, overseer of the Digit Fund she founded for gorilla protection in 1980, "and no one to give it to."

She came to Central Africa in the late '60s after working in Louisville as an occupational therapist. Former patients from the Kosair Hospital for Crippled Children remember her as a six-foot, suntanned Californian partial to gold jewelry and tasteful clothes. She drove a sports car. Her specialty was helping children with crippled arms and hands.

"Kids would get tired or frustrated and wanted to quit," a former patient remembered. "She wouldn't let you. She was tough, but it was because she cared about us." To delight the children, Fossey lured squirrels from nearby woods to take food; in her spare time she painted a "Wizard of Oz" mural to cheer up a drab examining room.

She set out to study gorillas with the blessing of noted paleoanthropologist Louis Leakey and headed for Zaire. When her camp there was overrun by Zairean rebels, she relocated in Rwanda, on the flat between two lofty volcanoes. Every morning Fossey would bolt a few crackers and coffee and set out, hiking miles up and down the slopes, returning to camp at night to stay up late typing and pondering her field notes. She sold her first article to the Louisville Courier-Journal, and assistants and research scientists interested in doing their own gorilla studies soon began to arrive.

Aware of the dangers of "getting bushy," as the phrase goes, she made an effort to maintain the social niceties essential to the peace and sanity of an isolated research station. She gave small dinners, cooking treats like spaghetti or chicken with great care, and she sent sprightly notes to camp assistants when she thought they needed cheering. Most of all, she relished her work.

"It never dawned on me," she wrote slyly, "that exhausting climbs along ribbons of muddy trail, bedding down in damp sleeping bags, awakening to don wet jeans and soggy boots, and filling up on stale crackers would not be everyone's idea of heaven."

She described gorillas as "the most maligned creatures on earth." Her research revealed the mountain gorilla as a shy vegetarian that mates for life and lives in highly structured social groupings led by senior males known as silverbacks for their mature coloring.

The mountain gorilla will fight to the death to defend one of its own, and it is for this reason that an attempt to capture one gorilla infant for a zoo or private collector can cause the death of as many as 15 gorillas in the same group.

In 1975 she left for Cambridge University to write her dissertation. "I've learned what intelligent and sociable animals these are," she wrote. "Fathers pluck infants from their mothers to groom them, and once I saw an old male tickle a youngster with a long-stemmed flower."

Photographs show her lying attentively on a soft bed of Galium vines, eyes closed in bliss as a 400-pound silverback gently grooms her face and a second, smaller female inspects a camera lens.

She prospered, appearing in numerous films and television specials, but over the years life at Karisoke changed. It could be seen in the titles of her National Geographic articles: "Making Friends With the Mountain Gorillas" in 1970 and "More Years With the Mountain Gorillas" gave way, by 1981, to "The Imperiled Mountain Gorilla." And now there was a subtitle: "A Grim Struggle for Survival."

By the late '70s, friends and acquaintances say, she had become difficult, more withdrawn, her behavior erratic. "One minute she could be wonderful, tender, open, self-deprecating," recalls Amy Vedder, a former research student. "The next minute she would be impossible."

Many of her friends traced the change to the death of a large male silverback called Digit, killed by poachers on New Year's Day in 1977, almost nine years to the day before Fossey herself was buried beside the gorilla graveyard at Karisoke.

She found the immense body sagged on the forest floor, long black fur caked with blood from several spear wounds and a red jagged hole where the head had been removed in hopes of selling it to a collector.

Digit and his band, she surmised, had had the misfortune to be grazing near an antelope trap-line when a group of poachers and dogs blundered by to check the snares. Terrified and enraged, Digit had held the equally terrified poachers at bay while the other members of group escaped to safety.

She had grown fond of all of the gorillas she studied but Digit had been a particular favorite: "I was unashamed to call him 'my beloved Digit,' " she wrote. Devastated by his death, Fossey retreated to her cabin for more than a week. She was further depressed several months later when two more gorillas were killed defending a 3-year-old offspring who had been shot through the shoulder in a capture attempt. By 1981 six of the 80 gorillas that Fossey and her researchers studied closely had been killed by poachers. The skeletal remains of 64 gorillas collected over the entire range led her to suspect that poachers had been involved in the deaths of many more.

Although increased vigilance and publicity had almost eliminated the international market for curios made from gorilla hands and feet and European zoos no longer clamored for infant gorillas, cattle herdsmen and antelope poachers continued to harass and destroy the gorillas.

In her misery, Fossey told friends she could no longer allow herself to become close to the gorillas. And although she had, in the disgusted words of a former researcher, "not a shred of evidence," she let it be known that she suspected some unscrupulous park officials had had a hand in more than one of the deaths.

She grew increasingly isolated. "I think she was terribly unhappy," recalls her friend Rosamund Carr. "I had letter after letter from her that said, 'I feel so alone.' "

Her health was not good. A junk-food addict, she suffered from calcium deficiency; a slipped disc had crippled her with sciatica, and she was having trouble breathing at the high altitude. She kept a oxygen pump beside her bed, but didn't cut her intake of the harsh local Impala-brand cigarettes. She was increasingly cabin-bound. Bill Weber, a researcher at camp in 1978-79, estimates that she ventured out on the steep mountain trails only a half-dozen times in the 18 months that he was there.

She had begun writing her book, "Gorillas in the Mist," but she found it difficult to work and her temper was frayed by the demands of her own increasing celebrity.

In 1979 she fired warning shots over the heads of a group of Dutch hikers who had strayed too close to camp. The horrified hikers retreated, but later wired an official protest, and Fossey was reprimanded.

She had always ruled camp with a firm and autocratic hand, addressed by staff as "madamoiselley," but she now sometimes blew up over minor things. A man who brought wet firewood to her door during a downpour would be excoriated and dismissed without wages. "Telemuka!" she would command angrily. "Go down!" And the man would head down the mountain, most often to be rehired later, but not always.

She would coldly dismiss the same work that she had found excellent the day before, behavior that mystified and irritated camp staff and mortified the white researchers who worked alongside them, according to former researcher David Watts.

The Africans in camp had an expression for her: "Kichwa yake ni sawa toto," Swahili for "her head is like a child's." It was an expression used to salve wounded pride after a particularly rough encounter. The jobs in camp paid a few dollars a day, however, good work in the impoverished area near the volcanoes. Men did not want to lose them. And there were compensations. For many years her trackers were better outfitted than the guards of the surrounding Parc des Volcans. A job in Fossey's camp gave a man a certain distinction. She could be generous with praise and occasional bonuses, and she always gave Christmas presents.

She clashed as well with many of the students and scientists who worked at camp. She felt threatened, these people say, by the bright, ambitious young PhD candidates. She needed to be stroked, and not everyone was willing to do it, particularly after they had been stung during an angry exchange.

"Dian had a way of starting off liking people, then something would upset her," says a defender. "She expected the same dedication from everyone. She expected every young person who went up there to have no other interest in life."

She insisted that researchers keep up-to-date field notes and file copies with her, a standard practice, but some students say she made liberal use of their observations in her book, published in 1983, without giving enough credit. She reportedly was hurt by monographs and doctoral theses that neglected to mention her name or Karisoke.

It was for poachers that she reserved her real venom. As long as her health permitted, she chased poachers through the woods herself, more than once pursuing them all the way to their villages. She once ripped matting from a poacher's hut and set it afire. On another occasion she left a village with a small child in tow and narrowly avoided being charged with kidnaping.

"She felt she had a right to punish people," said an acquaintance, "and of course she was a great trial to our American ambassadors. They either worshiped the ground she walked on or . . ."

When poachers were caught, they were hauled into Fossey's living room for interrogation and vilification. She was careful never to lay a hand on them herself and confined her efforts to theatrical and, as the years went by, almost stylized rebuke. "She would shout and spit and do everything she could to make them feel they were the scum of the earth," said Redmond. She prided herself on her network of spies.

According to former camp residents, at least one poacher was whipped with stinging nettle plants. (Some Rwandans say that was a traditional punishment until it was outlawed several years ago.) On another occasion, a camp researcher reported with horror that a poacher had been bound and a noose lowered around his neck. The threat was not carried out.

Her tactics inevitably put her in conflict with the people who live in the primitive villages on the park's fringe. Rwanda is the most densely populated country in Africa, mountainous, poor and overwhelmingly rural. The average farm is 2.5 acres ("It's not farming, it's gardening," says a French agronomist), and every available inch of land is under cultivation.

The rain forest of the Parc des Volcans is a large island of virgin, fertile land, and not surprisingly, many people, herdsmen particularly, look at it longingly.

Paid labor is scarce and poachers, for whom the park boundaries mean little, see the antelope inside as a valuable source of income.

Fossey was not unaware of their problems. It was just that she thought the gorillas were equally important, and she did not see any room for compromise.

Over the years she learned the rudiments of sumu, the local black magic. She knew the local people wore amulets and sacred pouches that were believed to insure strength and safety to the wearer. Many in the local population feared her as a white witch.

"She always used to say 'If you're alone and they bring a poacher up here, get his pouch,' " said Wayne McGuire, a graduate student who was working at camp when Fossey died.

In 1983 Dian Fossey had returned to Rwanda in improved health and spirits after a three-year hiatus in Ithaca, N.Y., where she had taught at Cornell University, lectured and finished her book. She came back to Rwanda, she told friends, because she felt she was needed at Karisoke. "The gorillas are dying," she said more than once, "and I'm going to die with them."

Her antipoaching war resumed, aided by money from the Digit Fund, a charity she had established in the United States. In 1984 she reported to the fund's directors that she had supervised the destruction of more than 2,200 snares. (Antelope poachers didn't usually set out to bag gorillas, but their accidental encounters with them were usually violent. Gorillas who got caught in snares often lost hands or feet, and the resulting gangrene was often fatal.)

Because the poachers were black, she forbade her African trackers from approaching too close in an effort to keep the gorillas wary of black faces. She was branded a racist by some, and ridiculed by scientists who said there was no proof that gorillas could distinguish between skin colors.

At the same time, Rwandan park and tourism officials were taking an increasingly dim view of her vigilante methods. She began to have trouble getting her visas renewed. "The Rwandans were finally trying to make the park a 20th-century operation," said an American anthropologist, "and she wanted to keep it a personal fiefdom." She was convinced that Rwandan tourism officials were trying to get rid of her so they could use her camp for tourism.

She disdained the efforts of a new conservation group with more diplomatic ideas because she was believed their work -- "gorilla tourism," education and efforts at antipoaching patrols -- were ineffective and siphoned funds away from her own efforts. "Blood money," she called it bitterly.

Several months before Dian Fossey's death her patrols arrested and brought to camp a man who had been found laying antelope traps. The poacher was brought into her living room and frisked. A small pouch was found sewn into the sleeve of his shirt. Fossey put it on the mantle. The man was distraught. When she went into her bedroom to retrieve money to reward his captors, he tried to wrench free and get the pouch back. He was sent down the mountain with park authorities without it. Fossey checked the contents -- bits of cloth and bark -- and tucked the pouch away for safekeeping.

Wayne McGuire did an inventory of her cabin in the days after her death. There were only two things that he couldn't find. One was her passport. The other was the pouch.

Dian Fossey's body was carried up and down the mountain twice, the first time in the mistaken belief that she would be buried in the United States. The first casket was too short and had to be rebuilt. In the meantime her body was stored in the refrigerator of a local business because there is no morgue in the capital city.

When the casket went up the narrow mud track to Karisoke for the last time, on a sapling stretcher borne by two dozen porters who had argued they could only make the trip in a team of 40, the grave had to be redug, because it was too small, too.