Among the hazards Napoleon Chagnon encountered in the Venezuelan jungle were a jaguar that would have mauled him had it not become confused by his mosquito net and a 15-foot anaconda that lunged from a stream over which he bent to drink. There were also hairy black spiders, rats that clambered up and down his hammock ropes and a trio of Yanomami tribesmen who tried to smash his skull with an ax while he slept. (The men abandoned their plan when they realized that Chagnon, a light sleeper, kept a loaded shotgun within arm’s reach.) These are impressive adversaries — “Indiana Jones had nothing on me,” is how Chagnon puts it — but by far his most tenacious foes have been members of his own profession.

At 74, Chagnon may be this country’s best-known living anthropologist; he is certainly its most maligned. His monograph, “Yanomamö: The Fierce People,” which has sold nearly a million copies since it was first published in 1968, established him as a serious scientist in the swashbuckling mode — “I looked up and gasped when I saw a dozen burly, naked, filthy, hideous men staring at us down the shafts of their drawn arrows!” — but it also embroiled him in controversy.

In turning the Yanomami into the world’s most famous “unacculturated” tribe, Chagnon also turned the romantic image of the “noble savage” on its head. Far from living in harmony with one another, the tribe engaged in frequent chest-pounding duels and deadly inter-village raids; violence or threat of violence dominated social life. The Yanomami, he declared, “live in a state of chronic warfare.”

The phrase may be the most contested in the history of anthropology. Colleagues accused him of exaggerating the violence, even of imagining it — a projection of his aggressive personality. As Chagnon’s fame grew — his book became a standard text in college courses — so did the complaints. No detail was too small to be debated, including the transliteration of the tribe’s name. As one commentator wrote: “Those who refer to the group as Yanomamö generally tend to be supporters of Chagnon’s work. Those who prefer Yanomami or Yanomama tend to take a more neutral or anti-Chagnon stance.”

In 2000, the simmering criticisms erupted in public with the release of “Darkness in El Dorado,” by the journalist Patrick Tierney. A true-life jungle horror story redolent with allusions to Conrad, the book charged Chagnon with grave misdeeds: not just fomenting violence but also fabricating data, staging documentary films and, most sensational, participating in a biomedical expedition that may have caused or worsened a measles epidemic that resulted in hundreds of Yanomami deaths. Advance word of the book was enough to plunge anthropology into a global public-relations crisis — a typical headline: “Scientist ‘Killed Amazon Indians to Test Race Theory.’ ” But even today, after thousands of pages of discussion, including a lengthy investigation by the American Anthropological Association (A.A.A.), there is no consensus about what, if anything, Chagnon did wrong.

Shut out of the jungle because he was so polarizing, he took early retirement from the University of California at Santa Barbara in 1999. “The whole point of my existence as a human being and as an anthropologist was to do more and more research before this primitive world disappeared,” he told me bitterly. He spent much of the past decade working on a memoir instead, “Noble Savages: My Life Among Two Dangerous Tribes — the Yanomamö and the Anthropologists,” which comes out this month. It is less likely to settle the score than to reignite debate. “The subtitle is typical Chagnon,” says Leslie Sponsel, an anthropologist at the University of Hawaii and a longtime critic of Chagnon. “Some will interpret it as an insult to the Yanomami and to anthropology in general.” Sponsel despaired that what is known as “the fierce controversy” would ever be satisfactorily resolved. “It’s quicksand, a Pandora’s box,” he said. “It’s also to some degree a microcosm of anthropology.”

When Chagnon first went into the jungle, in 1964, the public image of anthropology was at its peak. Claude Lévi-Strauss’s “Tristes Tropiques,” his magisterial memoir of his years studying tribes in Brazil, had recently been translated into English, prompting Susan Sontag to declare anthropology “one of the rare intellectual vocations that do not demand a sacrifice of one’s manhood. Courage, love of adventure and physical hardiness — as well as brains — are used by it.” “Dead Birds” (1963), Robert Gardner’s depiction of ritual warfare among the Dani people of New Guinea, was greeted as a landmark of ethnographic filmmaking. In the “Stone Age” culture of the Dani, anthropologists believed they had a snapshot of human development at a crucial early stage, and rumors of other “uncontacted” tribes fueled fantasies of genuine discovery. Membership in the A.A.A. doubled between 1960, when Margaret Mead, the field’s pre-eminent authority, served a term as president, and 1968.

Chagnon was well cast for life in the field. A 26-year-old graduate student at the University of Michigan, he grew up poor in rural Port Austin, Mich., the second of 12 children. He was self-sufficient and handy with a shotgun — minimum requirements for surviving on jungle terrain where the nearest airstrip was several hours downstream by motorized canoe. “It’s the harshest environment in the world, physically speaking,” Kenneth Good, an anthropologist at New Jersey City University, who accompanied Chagnon to Venezuela in 1975 and eventually married a teenage Yanomami woman, told me. “I nearly died of malaria several times.”

Today, Chagnon’s own health is fragile. He had open-heart surgery in 2006 — “a likely consequence of the attacks on me,” he says — and suffers from a lung condition that keeps him tethered to a portable oxygen tank much of the time. Still, when I met him in January, at his home in a wooded subdivision near the University of Missouri in Columbia, where he and his wife, Carlene, had just moved so that he could take up a new position in the anthropology department, he had half a dozen pheasants in his freezer, quarry from a recent hunting expedition with his German shorthaired pointer, Darwin. “Pheasant breast on toast with butter is one of the more delicious breakfasts I’ve ever eaten,” he said solemnly.

In his baseball cap and faded jeans, with a thermos of Heineken at his side, he seemed a pointed rebuke to Ivory Tower decorum. The house, a cavernous brick two-story, was only partly furnished — the Chagnons had lived there all of 10 days. But elegantly arrayed along a ledge above the mantel were a couple dozen woven baskets, like so many households around the rim of a shabono — the vine-and-leaf structure that encloses an entire Yanomami village.

Chagnon’s account of his first encounter with the tribe is legendary: he crept through the low entrance of a shabono, startling a group of Yanomami warriors — the dozen “filthy, hideous men” — who had just concluded a bloody club fight with a neighboring village over the abduction of seven women. “Immense wads of green tobacco were stuck between their lower teeth and lips making them look even more hideous,” Chagnon wrote, “and strands of dark-green slime dripped or hung from their noses.” (The green snot was a side effect of ebene, a hallucinogen that the Yanomami blow into one another’s nostrils.)

By the end of that first day, Chagnon knew he needed to rethink what he had been taught. Apart from a handful of reports by missionaries and European ethnographers, little was known about the Yanomami, who were scattered among several hundred shabonosacross roughly 70,000 square miles on the Venezuelan-Brazilian border. According to the reigning “cultural materialist” doctrine — which owed as much to Marx as to the noble-savage ideal — conflict among groups arose only when there was competition for strategic resources: food, tools, land. The Yanomami in Bisaasi-teri, the shabono that Chagnon had entered, appeared not to be lacking these things. They shouldn’t have been fighting with their neighbors, and certainly not over women — that kind of reproductive competition, cultural materialists claimed, had nothing to do with warfare. During Chagnon’s initial 17 months in the field, one nearby village was raided 25 times. “I began realizing that my training in Michigan was not all that it was supposed to be,” he said.

He spent his first few months trying to learn the villagers’ names and kinship ties, a standard practice at the time and a particular challenge in this case, given the Yanomami’s name taboos: to call someone by his name is often an insult, and the names of the dead aren’t supposed to be uttered at all. Chagnon rewarded informants with fish hooks, matches and, for men who really dished, knives and machetes. (The Yanomami made no metal tools themselves.) Then, on a visit to another village, Chagnon cautiously mentioned the names of the Bisaasi-teri headman and his wife. The residents burst out laughing. He realized that he’d been had: the names he’d been given were slang for genitalia.

Genealogies became Chagnon’s driving obsession. They were crucial for tracing patterns of reproduction — determining which men had the most offspring or how many had wives from other villages. By the end of his last trip to the jungle, in 1995, Chagnon had data on about 4,000 Yanomami, in some cases going back to the 19th century. “That’s what he lives for,” Raymond Hames, an anthropologist at the University of Nebraska who worked with Chagnon as a graduate student, told me. “To collect the data, update the data, crosscheck it. He’s incredibly meticulous.”

Genealogies could also be useful for understanding genetic variations within social groups — then a new avenue of research. Before leaving Ann Arbor, Chagnon met with James V. Neel, a prominent geneticist at the university’s medical school, to propose a collaboration. Neel was best known for his genetic studies of survivors of the Hiroshima and Nagasaki bombings. But he was interested in indigenous populations, in part because, having never been exposed to atomic radiation, they could provide a base line for comparison. After taking samples of the Yanomani’s blood, Neel discovered that the tribe’s levels of heavy metals and other environmental toxins were similar to Westerners’. They also lacked immunity to measles. In 1968, Chagnon helped Neel’s team vaccinate 1,000 Yanomami against the disease, just as it broke out near Bisaasi-teri.

Chagnon believed that biology was essential to understanding the tribe’s warfare over women. After all, more women meant more opportunities to pass on genes through reproduction — a basic tenet of evolutionary thought. But biology had no place in the cultural-materialist paradigm. And explanations of human behavior that relied on evolutionary theory were typically met with suspicion in anthropological circles, a legacy of the American eugenics movement, which invoked Darwinian ideas to justify racist efforts to “improve” the gene pool. “The last bastions of resistance to evolutionary theory,” Chagnon told me, “are organized religion and cultural anthropology.”

Marvin Harris, the leading cultural materialist and a professor at Columbia, was adamant that the Yanomami could not be fighting over women, and in 1975, he threw down a gauntlet. One of Harris’s former students, Daniel Gross, had just published a paper arguing that a scarcity of animal protein led to conditions that favored violence among Amazonian tribes, a theory Harris enthusiastically adopted. Chagnon, who had taken a job at Penn State, and three graduate students met with Harris in New York, on their way to Venezuela. “Harris said, ‘If you can show me that the Yanomami get the protein equivalent of one Big Mac per day, I’ll eat my hat,’ ” recalled Chagnon, who accepted the challenge.

By then Chagnon was waging battles on several fronts. That year, the Harvard biologist Edward O. Wilson published “Sociobiology,” to the dismay of many anthropologists, who were appalled by what they perceived as Wilson’s attempt to reduce human social behavior to an effect of genes. But Chagnon was excited by Wilson’s ideas, and in 1976 he and a colleague arranged for two sessions on sociobiology to take place at the annual A.A.A. convention. The evening before the sessions, several scholars moved to prohibit them. “Impassioned accusations of racism, fascism and Nazism punctuated the frenzied business meeting that night,” Chagnon writes in “Noble Savages.” Only after Margaret Mead denounced the motion as a “book burning” was it defeated.

At the same time, Chagnon’s portrayal of Yanomami aggression was meeting with increasing resistance. One theory had it that his habit of rewarding cooperative subjects with steel tools — common practice at the time — worsened conflicts. Jacques Lizot, a French anthropologist who spent more than 15 years in a village near Bisaasi-teri, wrote that he hoped to “revise the exaggerated representation that has been given of Yanomami violence. The Yanomami are warriors; they can be brutal and cruel, but they can also be delicate, sensitive and loving.” These latter traits also appeared, though less prominently, in Chagnon’s work. In “The Fierce People,” he recounts the night he became “emotionally close to the Yanomamö for the first time.” A village headman had been killed in a raid, and his brothers were audibly mourning his death. Moved, Chagnon lay quietly in his hammock, not wanting to intrude with his tape recorder or notebook. When asked why he was not “making a nuisance of himself as usual,” Chagnon explained that he was sad. This news was quickly passed around, and for the rest of the night he was treated with great deference: “I was hushuo, in a state of emotional disequilibrium, and had finally begun to act like a human being as far as they were concerned.”

What could have been fruitful academic debates became personal and nasty. It didn’t help that Chagnon could be arrogant and impolitic. “Oh, God, did we have some fights in the field,” says Raymond Hames, who accompanied him on the 1975 protein-challenge trip. “He’s pretty damn sure of himself.” Hames, who remains a close friend, says he and Chagnon “made it work out.” But this was not the case with others.

Kenneth Good was also on the trip and was delegated to study protein consumption at a village far upstream from Bisaasi-teri. Chagnon, he says, refused to give him a steel boat or replenish his anti-malaria pills and didn’t care that he capsized and was stranded without food for three days. “If he had behaved in a civil way, we could have been lifelong allies,” Good told me. (Chagnon says that Good’s demands were unreasonable: “He wasn’t civil to me from the very beginning. I took him into the most exciting field opportunity that existed in anthropology at the time, and he never even sent me a progress report.”)

After Good returned to the United States, he left Chagnon’s department and finished his dissertation with Harris. When the protein studies were finally published, the findings, perhaps unsurprisingly, were split: Good showed that the Yanomami in his village ate slightly less protein than what’s in a Big Mac; Chagnon and Hames showed that their group ate much more. Daniel Gross, who recently retired from the World Bank, says the debate remains unresolved. He pointed out that the Yanomami are about five feet tall, on average. “You have to wonder what accounts for their low stature,” he said. “It’s most likely not a genetic trait.”

Chagnon also fell out with Lizot, the French anthropologist, and with Timothy Asch, an ethnographic filmmaker with whom he collaborated on more than a dozen documentaries. The partnership yielded ingenious work, including “A Man Called ‘Bee’ ” (1974), in which the camera turns, for once, on the ethnographer. Chagnon strides into the middle of a shabono in a loincloth and faded high tops and strikes a warrior pose — a bearded Tarzan aping his subjects, to their audible delight. (The film’s title comes from Chagnon’s Yanomami nickname, “Shaki,” their word for a particularly pesky species of bee.) But by 1975, with the release of “The Ax Fight,” a prizewinning record of a Yanomami brawl, Chagnon and Asch’s own fighting, mostly over who should get top billing in the credits, had destroyed their relationship.

Nor did Chagnon manage to stay on good terms with the local Salesian priests, who, thanks to their influence in Caracas, had considerable say over which scientists got to work with the tribe. In 1993, Chagnon attacked the Salesians in an Op-Ed in The New York Times, charging that the Yanomami were using mission-issued guns to kill one another. The Salesians fought back, depositing anti-Chagnon leaflets at the annual A.A.A. convention and mailing packets of letters — including one from Lizot — to anthropology departments across the country, denouncing his claims.

Chagnon sensed that his access to the Yanomami was ending. Anthropology was changing, too. For more than a decade, the discipline had been engaged in a sweeping self-critique. In 1983, the New Zealand anthropologist Derek Freeman delivered a major blow when he published “Margaret Mead and Samoa,” charging that Mead had been duped by informants in her pioneering ethnography, “Coming of Age in Samoa.” Postmodern theory precipitated a crisis. Under the influence of Derrida and Foucault, cultural anthropologists turned their gaze on their own “texts” and were alarmed by what they saw. Ethnographies were not dispassionate records of cultural facts but rather unstable “fictions,” shot through with ideology and observer bias.

This postmodern turn coincided with the disappearance of anthropology’s traditional subjects — indigenous peoples. Even the Yanomami were becoming assimilated, going to mission schools, appearing on television in Caracas and flying to the United States to speak at academic conferences. Traditional fieldwork opportunities may have been drying up, but there was still plenty of work to do exposing anthropologists’ complicity in oppressing “the other.” As one scholar in the journal Current Anthropology put it, “Isn’t it odd that the true enemy of society turns out to be that guy in the office down the hall?”

One way to confront the field’s ethical dilemmas was to redefine the ethnographer’s role. A new generation of anthropologists came to see activism on their subjects’ behalf as a principal part of the job. Chagnon did not; to him, the Yanomami were invaluable data sets, not a human rights cause — at least not primarily. In 1988, he published a provocative article in Science. Drawing on his genealogies, he showed that Yanomami men who were killers had more wives and children than men who were not. Was the men’s aggression the main reason for their greater reproductive success? Chagnon suggested that the question deserved serious consideration. “Violence,” he speculated, “may be the principal driving force behind the evolution of culture.”

The article was seized on by the press, including two newspapers in Brazil, where illegal gold miners had begun invading Yanomami lands. The Brazilian Anthropological Association warned that Chagnon’s “dubious scientific conclusions” could have terrible political consequences: “Wide publicity about Yanomami ‘violence’ in racist terms . . . is being used by the powerful lobby of mining interests as an excuse for the invasion of these Indians’ lands.”

As Alcida Ramos, a Yanomami expert at the University of Brasilia, later explained to Science: “To do anthropology in Brazil is in itself a political act. We don’t separate our interests as anthropologists from our responsibility as citizens.” Her colleague Bruce Albert told Science that a plan by the Brazilian government to divide the tribe’s land into a series of disconnected “islands” was being justified by claims that, as the reporter put it, the Yanomami “are violent and need to be kept separate so they will stop killing each other.” Nevertheless, the reporter noted, Albert “cannot demonstrate a direct connection between Chagnon’s writings and the government’s Indian policy.”

Scientists have since endorsed Chagnon’s Science article. “It shouldn’t be a shocking finding,” Steven Pinker, the Harvard evolutionary psychologist who cites the paper in his book, “The Better Angels of Our Nature: Why Violence Has Declined,” told me. “As a pattern in history, it’s well documented.” Pinker said that he was troubled by the notion that social scientists should suppress unflattering information about their subjects because it could be exploited by others. “This whole tactic is a terrible mistake: always putting your moral action in jeopardy of empirical findings,” he told me. “Once you have the equation that the Yanomami are nonviolent and deserve to be protected, the converse is that if they are violent they don’t deserve to be protected.”

Chagnon had alienated most of the anthropologists in Venezuela and Brazil who might have helped broker his visits to the tribe. In 1990, desperate to return to the jungle, he accepted an invitation from an old contact, Charles Brewer-Carías, to serve as an adviser to Fundafaci, a Venezuelan foundation established by Cecilia Matos, the consort of President Carlos Andrés Pérez, to help the country’s poor. The association proved disastrous for Chagnon. Brewer-Carías, a well-connected dentist and former Venezuelan youth minister, had been accused of illegally mining for gold on Yanomami land. (Brewer-Carías has denied the allegations.) “He’s a dapper opportunist,” Chagnon told me. “Charlie can talk his way into and out of just about everything.”

For months, Fundafaci helicopters flew in and out of some of the most pristine Yanomami settlements, ferrying researchers, television crews and the occasional wealthy tourist — as well as, inevitably, their germs. According to Patrick Tierney, during one helicopter landing, several Yanomami were injured when the roof of a shabono collapsed. Chagnon and Brewer-Carías also urged President Pérez to turn part of the region into a biosphere, which, Tierney writes, would have given them “a scientific monopoly over an area the size of Connecticut.” The A.A.A., which appointed an El Dorado task force to look into Tierney’s allegations, concluded that this charge could not be proved, since Pérez abandoned the Fundafaci proposal. But the task force was harshly critical of Chagnon, stating that his affiliation with Fundafaci “violated Venezuelan laws, associated his research with the activities of corrupt politicians and involved him in activities that endangered the health and well-being of the Yanomami.”

The adventure came to an end in 1993, when Pérez was impeached. Chagnon, characteristically, is unrepentant. “I got a year’s worth of data,” he said. “It was worth it for that reason.”

Was Fundafaci an isolated case of bad judgment, or part of a pattern of ethically egregious behavior? Tierney’s “Darkness in El Dorado,” which he spent more than a decade reporting, took the latter view and was eagerly anticipated by Chagnon’s critics: the moment when a rogue anthropologist would get a rare public comeuppance. In August 2000, while the book was still in galleys, Leslie Sponsel, of the University of Hawaii, and Terence Turner, an anthropologist at Cornell, sent an e-mail to the A.A.A.’s leadership, warning of an “impending scandal,” unparalleled in its “scale, ramifications and sheer criminality and corruption.” In lurid detail, they laid out the book’s major allegations, concluding: “This nightmarish story — a real anthropological heart of darkness beyond the imagining of even a Josef [sic] Conrad (though not, perhaps, a Josef Mengele) — will be seen (rightly in our view) by the public, as well as most anthropologists, as putting the whole discipline on trial.”

By November, when the A.A.A. met for its annual meeting, the scandal had hit the press, and “Darkness in El Dorado” had been excerpted in The New Yorker and named a finalist for the National Book Award. Much of the coverage focused on Tierney’s most sensational charges regarding the 1968 measles epidemic.

In his galleys, Tierney speculated that Neel, who died in 2000, hoped to simulate a measles epidemic among the Yanomami as part of a genetics experiment. In the published book, this theory was no longer explicit — Tierney had made last-minute changes — but it was insinuated. “Measles,” Tierney wrote, “was tailor-made for experiments.” Moreover, Neel’s choice of vaccine, Edmonston B, “was a bold decision from a research perspective” because it “provided a model much closer to real measles than other, safer vaccines, in the attempt to resolve the great genetic question of selective adaptation.” Although he quoted a leading measles researcher emphatically denying that measles vaccine can transmit the virus, he nevertheless maintained that it was “unclear whether the Edmonston B became transmissible or not.” (This line was excised from the paperback edition.) Tierney repeatedly faulted the expedition’s members for putting their scientific objectives ahead of the tribe’s health. By vaccinating the Yanomami against measles, he maintained, Neel and Chagnon may have been responsible for needless illness and death.

At an open-mike A.A.A. session, attendees, few of whom had read the book, weighed in on the controversy. Thomas Gregor and Daniel Gross later described the event in a damning article in American Anthropologist: “Virtually every aspect of [Chagnon’s] behavior, relevant or otherwise, was open for public dissection. One participant took the microphone and claimed that Chagnon had treated her rudely in the field during the 1960s. A colleague from Uganda praised Tierney’s book and suggested that Westerners manufactured the Ebola virus and disseminated it in his country, just as Chagnon and Neel had started the measles epidemic. Members of the audience applauded both speakers.” For Gregor, who recently retired as an anthropologist at Vanderbilt, the session was “a watershed moment.” “These are people who are supposed to be scientists,” he told me. “This had the look of an emotionally charged witch hunt.”

Within a few months, half a dozen academic institutions had refuted aspects of Tierney’s claims, including the International Genetic Epidemiology Society, whose statement reflected a growing consensus: “Far from causing an epidemic of measles, Neel did his utmost to protect the Yanomamö from the ravages of the impending epidemic by a vaccination program using a vaccine that was widely used at the time and administered in an appropriate manner.” (In an e-mail to me, Tierney defended his book, acknowledging only “several small errors,” concerning Neel’s work in Japan.)

The A.A.A.’s El Dorado task force was the most ambitious investigation to date but was undermined by a lack of due process. The group went so far as to interview Yanomami in Venezuela but, according to Chagnon, failed to give him an opportunity to respond to its verdicts. As Gregor and Gross put it, what the inquiry most clearly demonstrated was not Chagnon’s guilt or innocence but rather anthropology’s “culture of accusation,” a “tendency within the discipline to attack its own methods and practitioners.”

At least one task-force member had doubts about the exercise. In April 2002, shortly before the group released its report, Jane Hill, the task force’s chairwoman and a former president of the A.A.A. wrote an e-mail to a colleague in which she called Tierney’s book “just a piece of sleaze, that’s all there is to it (some cosmetic language will be used in the report, but we all agree on that).” Nevertheless, she said, the A.A.A. had to act: anthropologists’ work with indigenous groups in Latin America “was put seriously at risk by its accusations,” and “silence on the part of the A.A.A would have been interpreted as either assent or cowardice. Whether we’re doing the right thing will have to be judged by posterity.”

The e-mail is quoted in a paper by Alice Dreger that appeared in the journal Human Nature in 2011. Dreger, a professor of bioethics at Northwestern, was writing a book about scientific controversies in the Internet age, when she learned about the scandal in anthropology. She researched the case for a year, conducting 40 interviews, and by the time she published her paper, she considered Chagnon a friend, a fact reflected in her sometimes zealous tone. Among other things, she discovered that Tierney helped prepare a dossier critical of Chagnon, which he attributed to Leda Martins, a Brazilian anthropologist: “Leda’s dossier was an important resource for my research.” (Martins says that she translated the dossier into Portuguese.) But Dreger reserves her most withering remarks for the A.A.A. She told me, “All these people knew that Tierney’s book was a house of cards but proceeded anyway because they needed a ritualistic cleansing.”

In fairness, Tierney seems to have gotten some things right. The task force called his account of Chagnon’s Fundafaci episode one of the “better supported allegations.” And many have vouched for Tierney’s description of Jacques Lizot, Chagnon’s French rival, ensconced in the jungle with an entourage of Yanomami boys, whom he plied with trade goods in exchange for sex. (Lizot has said that the sex was between consenting adults.)

Yet it’s possible to imagine how a discipline seeking to expiate its sins could have overreached in Chagnon’s case. He was prominent and controversial, a sociobiologist who declined to put activism on a par with research. On the rare occasions that he adopted the mantle of advocate, the gesture typically backfired, as when he told a Brazilian magazine: “The real Indians get dirty, smell bad, use drugs, belch after they eat, covet and sometimes steal each other’s women, fornicate and make war. They are normal human beings. This is reason enough for them to deserve care and attention.” His critics, appalled by the first sentence, typically ignored the rest.

In this charged atmosphere, Tierney was to play a vital role: that of the impartial journalist who would give the discipline’s verdict on Chagnon the stamp of objectivity. Yet as Tierney himself admitted, he was not impartial. “I gradually changed from being an observer to being an advocate,” he wrote. “It was a completely inverted world, where traditional, objective journalism was no longer an option for me.” Was objectivity possible for anyone?

In 2005, the A.A.A.’s members agreed to rescind the task-force report, by a vote of 846 to 338. Daniel Gross called Chagnon to give him the news. “I saved that phone message for years,” Chagnon told me. “That was the point at which my emotional stability began to ascend.” Last spring, he was elected to the National Academy of Sciences — a prestigious honor that he took as vindication. “A lot of anthropologists have red faces from the extent to which they advocated in support of the accusations against me,” he said.

Not every critic has conceded. “The charges have not all been disproven by any means,” Leslie Sponsel pointed out. Leda Martins, who teaches at Pitzer College in Los Angeles, was more circumspect. “The controversy is so big, and the devil is all in the details,” she said. “Unless you know where Chagnon was, in what village, and what he was doing — unless you know everything — it’s really hard to talk about it.” I told her I thought that Tierney was sure he’d found another Kurtz, another “Heart of Darkness.” “Patrick and Chagnon have some similar characteristics,” Martins replied. “How ironic is it that Patrick got carried away in the same way that Chagnon got carried away?”

By now, at least a few Yanomami have read both “The Fierce People” and “Darkness in El Dorado,” and many more have been told about their contents by people with varied agendas. During an interview with a member of the A.A.A.’s task force, Davi Kopenawa, a Brazilian Yanomami leader, was invited to pose some questions of his own. “I want to ask you about these American anthropologists,” he said. “Why are they fighting among themselves? Is it because of this book?”

The interviewer answered in the affirmative, and Kopenawa went on: “So, Chagnon made money using the name of the Yanomami. He sold his book. Lizot, too. I want to know how much they are making each month. How much does any anthropologist earn? And how much is Patrick making? Patrick must be happy. This is a lot of money. They may be fighting, but they are happy. They fight, and this makes them happy.”