In October 2000, two months after Burning Man, I visited the Secoya Indians, a small tribe of 750 in the Ecuadorean Amazon. The Secoya live on the Rio Aguarico, a river winding through the largest unroaded stretch of rainforest left in the world. Later I found out that the Secoya are respected among the neighboring Indian groups for the purity of their ayahuasca traditions. Like many Amazonian tribes, the Secoya have been decimated over the last century by disease and forced acculturation. Their last great shaman is Don Caesario, a small and frail man in his eighties.

"The Secoya culture is based on communion with the 'heavenly people' who live along the river and in the sky," said Jonathon, the ethnobotanist who organized my trip. "They drink yagé to see them."

Don Caesario usually maintained the distanced but regal demeanor of someone with command over the deep mystical realms. He resembled a high Tibetan lama, with Asiatic features and the large ears of the spiritually advanced. He was often seated quietly on a hammock, wearing crisscrossing necklaces made from painted seeds, a knee-length white tunic, and a yellow crown - the traditional garb of the Secoya.

On my first morning in the jungle, Don Caesario stood inches away from me in a long dugout canoe. He did not radiate calm. He was shaking with rage, brandishing a loaded shotgun. A few days ago, Don Caesario's personal canoe and outboard motor - worth about $4,000, a lifetime's wages for the average Secoya - had been stolen. The shaman demanded vengeance.
The expedition included a group of male Secoyas ranging from elders to young boys. Also a few of the assistants employed by Sentient Experientials, the tour group, as well as four foolish tourists including myself. At the helm of the boat, John Bella, a gung-ho rainforest activist and junior member of the Sentient staff held a hunting rifle that I hoped he wouldn't try to use. The Sentient staff was a nebulous group that included a Californian healer, a sullen Colombian masseuse, a shaggy-bearded cook, others whose roles I never figured out, and some Quechua Indians. Also traveling with us was Pablo Amaringo, a painter known for his wonderful and intricate renderings of ayahuasca visions. A gentle man and art teacher, Amaringo had been a Peruvian ayahuasquero for many years, drinking yagé every day. He said he started to have visions of a witch who was trying to kill him every time he took yagé. He realized that he would have to kill her if he wanted to remain a shaman. He decided to give up his practice instead.

I was sitting next to Mark Miller, a psychologist in a tie-dyed T-shirt.

"What am I doing here?" Mark asked, as the canoe churned the waters of the Aguarico River, a muddy channel flowing from Ecuador to Colombia. "I've got a wife and baby back home."

Don Caesario raised his gun. In Spanish he shouted, "I will kill the thieves when I find them."

Mark and I had been invited along by Jonathon Miller-Weisberger, a Berkeley-born, Ecuador-raised, Jewish botanist with a penchant for quoting the Tao. He had organized this tour. He was also the founder of Grupo Osanimi, an organization that works on cultural-revival projects with Ecuadorean tribes. Most of the profits from this trip would go to benefit Grupo Osanimi's projects. During our two weeks in the jungle, Jonathon wanted us to get a full dose of Amazonian life. He explained that theft along the Aguarico, once almost unheard of, was becoming common as conditions deteriorated: Mestizos were settling on isolated plots of land between the territories belonging to the Siona, the Secoya, and the Quechua. They eked out a living by growing coffee beans and corn, and the most unscrupulous among them tried to take advantage of the Indians. Meanwhile, the U.S. government was pouring $1.5 billion into "Plan Colombia," making war on the guerillas and attempting to annihilate the coca fields hidden along the Ecuadorean-Colombian. From planes, they were spraying massive amounts of "Round-Up," an extremely poisonous herbicide developed by Monsanto, that apparently laid waste to large swathes of the jungle, destroying uncountable species including ayahuasca - even poisoning the fish in the rivers, according to the Indians. It was unknown to what extent the underground coca industry was damaged by this indiscriminate assault. The Secoya feared Colombian guerrillas sneaking into Ecuador - in fact, the guerrillas might have stolen the canoe. To add to the anxiety, we were in a region where desperadoes had been kidnapping American and European oil-company workers with alarming regularity. The tension thickened to match the equatorial humidity as we scanned the silent, sticky jungle for enemies.

After several hours, we came upon the canoe chained in front of a ramshackle homestead. A path from the riverbank led up to thatched huts shaded by the shiny leaves of coffee bushes. Families - a few scared men, mothers, children, blacks and Mestizos in cheap Western clothes - watched us hesitantly from the shore. It was impossible to read their faces. Were they guilty and ashamed? Cunning and deceitful? Were other settlers, rifles drawn, targeting us from behind the trees?

Don Caesario and some of the Secoya jumped into the canoe and cut it loose. Heated words were exchanged. The shaman's lips trembled in fury as he raised his shotgun and pointed it at the frightened leaders of the homesteaders.

Mark and I looked at each other. We were caught between our shaman's sight line and his enemies. It did not seem like a safe place to be.

Jonathon leapt out of the boat and stepped in front of the settlers. The Secoya gunned the motor and piloted Don Caesario away. Shots rang out - the sound of our spiritual leader emptying his chambers into the air.

We met Jonathon in Quito, Ecuador's capital, where the country's sudden switch to a U.S.-dollar economy, due to an IMF-engineered debt crisis, was spurring massive inflation and riots. Our group was booked at Casa del Sol, a small hotel staffed by Quechua Indians, on Avenida Jose Calama. Calama was turista central, a street of hotels, bars, and hostels. Recently wired to the Net, it was home to an alarming number of new cyber cafes - pool.net, papaya.net, earth.net - each one blaring pop music and selling multihued fruit drinks. Young backpackers, ranging from the hip and dreadlocked to the preppy and generic, sat before banks of terminals, e-mailing their friends back home about their romantic hook-ups, visa problems, and stomach aches. But the multicultural buzz of the cafes was dampened by the guards in black uniforms who stood in the street with dogs and automatic weapons, protecting the gringos from the ever-present threat of kidnappers and thieves.

Jonathon had rented a bus to take us from Quito. We drove through the cloud forests of the Andes, descending into the Amazon in a bumpy twelve-hour ride. This ride tattooed on our eyeballs the devastation wrought by the oil industry. The roads built by the oil companies had opened up the jungle to loggers and poor, desperate Mestizo settlers. All thoughts of visionary Indians and mystic revelations were wiped away by the blunt reality of the pipeline running inexorably beside the road, surrounded by recently clear-cut land, sucking the marrow out of the jungle.

We spent the night at Lago Agrio, the Dodge City of Ecuador, population twenty-five thousand and growing. It was a ragged boomtown of two industries: oil and prostitution. Ten years ago, the area was virgin rainforest; now it was slashed-and-burnt scrub. Once it is destroyed, the rainforest does not regenerate itself, and the local climate quickly becomes too hot and dry for farming. The land, for all practical purposes, becomes useless.

Our bus driver and his buddy returned with sheepish grins from a night on the town. They bragged about the teenage prostitutes who could be had for $2 at the local whorehouses. I thought of the chain of dehumanization and exploitation beginning with the oil company's quest for profit, the American consumer's avidity for cheap gas to fuel SUVs, the corrupt governments of bankrupt Third World countries seeking payoffs, ending with despoiled rainforests and teenage Mestizo girls contracting AIDS from drunk ditch diggers in Third World backwaters. Benjamin's "religion of destruction" was performing its good works.

The next day, we rode for four hours on motorized canoes, on the mud-brown Rio Aguarico, ever-deeper into the jungle, surrounded by its secretive green density. We passed through the territories of neighboring Indian tribes. As night fell, we were brought to the rough stone steps leading up to the house of Don Caesario.

Over the last three hundred years, the Secoya have lost their ancestral homeland and 98 percent of their population. Decimated by the diseases of the Spanish conquerors, enslaved and forced to work on rubber plantations, a tribe of more than thirty thousand has been reduced to a paltry 750. Almost half live on the Rio Aguarico, the rest in the remote jungles of Peru.

Across the Amazon, Indian cultures have been compromised and quickly destroyed through contact with the West. Vast treasures of botanical knowledge and linguistic and spiritual traditions are already gone. As the force of the colonialists and their Christian missionaries overwhelmed the Indians, followed by ruthless rubber tappers and then even more ruthless oil corporations, the tribal shamans lost their authority. Many were accused - often by missionaries - of witchcraft. Shamans have been murdered by Indians looking for scapegoats to blame for the collapse of their world.

In the U.S. and Europe, shamans have been reappropriated as heroic figures by anthropologists, psychedelic avatars like Terence McKenna, and New Age popularists. But the fact is that ambiguity hovers over shamanism wherever it appears. The magical powers acquired through disciplined use of ayahuasca can be turned to good or evil. The Yagé Drinker is the autobiography of the famous Secoya shaman Fernando Payaguaje, compiled from interviews with his grandsons. Payaguaje spoke about the temptation of sorcery: "Some people drink yagé only to the point of reaching the power to practice witchcraft; with these crafts they can kill people. A much greater effort and consumption of yagé are required to reach the highest level, where one gains access to the visions and powers of healing." Michael Harner, studying the shamanism of the Jivaro (or Shuar) Indians of the Amazon, noted that Jivaro shamans wielded magical darts, tsentsak, that could be used either to cure or kill. The Jivaro, like most tribal groups, lived in constant fear of witchcraft. Sorcery is the inescapable shadow side of shamanism.

The modern West, engaged in a neo-shamanic renaissance, has so far ignored the ambiguous aspects of shamanism. The American anthropologist Michael F. Brown finds it unsettling "that New Age America seeks to embrace shamanism without any appreciation of its context. For my Santa Fe acquaintances, tribal lore is a supermarket from which they choose some tidbits while spurning others." Among the Indians, "Shamanism affirms life but also spawns violence and death. The beauty of shamanism is matched by its power - and like all forms of power found in society, it inspires its share of discontent."

Westerners who have rediscovered magic and spirit as living facts of human existence - transformed in their own inner being by the knowledge - yearn to reintroduce these forces to the contemporary world. Yet these elemental forces cannot be divorced from ambiguity, from danger. The power can be easily misused or distorted. Magic shades into witchcraft, communicating with the spirit realm is a step away from occult invocation. Bringing this knowledge back into contemporary life requires reckoning with dark forces - a balancing act which is also part of indigenous shamanism.

"Ayahuasca tourism," a growing phenomenon throughout South America, reflects the surge of underground interest in ayahuasca in the United States. Precise figures are hard to come by, but one could estimate there are hundreds of shamans, ranging from authentic to ambiguous to fraudulent, receiving thousands of Western visitors annually. Websites devoted to the vine keep multiplying, along with new books: The Cosmic Serpent, by Jeremy Narby; Ayahuasca: Human Consciousness and the Spirits of Nature, edited by Ralph Metzner; and Ayahuasca Visions, by Pablo Amaringo and Eduardo Luna, to name only a few. Magazines like Shaman's Drum promote group tours to visit Mestizo shamans across the Amazon for a few weeks of fasting and "journeying."

Some critics attack these excursions for marketing native spirituality and further degrading Amazonian traditions. The anthropologist Marlene Dobkin Del Rios, author of Visionary Vine, a book on yagé healing in Peru, believes that Americans are driven to shamanic adventures by the syndrome of the "empty self," the inner void left by our materialistic culture. In the introduction to his book Ayahuasca Analogues, Jonathan Ott bemoans ayahuasca tourism in the Amazon, "which can only disrupt the evanescent remnant of preliterate religiosity struggling to make a place for itself in the modern world, while attracting the wrong kind of political attention to ayahuasca."

It seems to me that these perspectives are short-sighted - not only because the shamans themselves have the vision of sharing their knowledge with Westerners, but also because yagé tourism, if it is done conscientiously, is a force that can help to preserve indigenous traditions at this point. This is what seems to be happening with the Secoyas. There are not going to be any "pure" Indian cultures anymore, certainly no illiterate ones. After decades of seeing their cultures trashed by the missionaries, assaulted by the Western governments, overrun by corporate emissaries, the Indians need to know that certain groups of rich Westerners value their knowledge and history. The yagé tours are, in fact, beneficial to both sides: The shamans desperately need the revenue, and we - equally desperately - need the revelations.

Sentient Experientials did not explicitly use yagé to promote their journeys to Secoya territory. Don Caesario was not paid for his shamanism - instead, he was compensated for his hospitality with gifts, such as his house and canoe. Beholden to no one, he could skip the ceremonies entirely if he did not like the energy of the group.

I fervently hoped he wouldn't do that to us.

After the recovery of the boat, we settled in for a twelve-day stay. The women set up tents, while most of the men slept on hammocks under the shaman's thatched roof, where the elders and an ever-rotating number of Secoya families also lived. Several times I returned to my hammock in the afternoon to find a tiny baby sleeping in it.

Among our group of hopeful psychonauts, the largest contingent, surprisingly, was made up of feisty middle-aged women - social workers, therapists, academics, and housewives - some white-haired, most wearing fanny packs and Tevas. Two were graduates of the California Institute of Integral Studies, a kind of New Age think tank. There was also Octavia Martin, a pensive Native American artist who lived on a reservation in Massachusetts. We did not seem likely candidates for a trek into the deep jungle; our campsite was a three-hour canoe trip away from a phone or hospital. I was especially worried about Annie Bush, a psychotherapist whose large body suggested the soft excesses of suburban living (later she outhiked me through the forest). There were two other guys in their thirties following a personal "vision quest."

"I do what the Great Spirit tells me to do," said Mark, the therapist, only half-joking. He had gone on a thousand-mile peyote hunt, the annual rite of the Huichol Indians in Mexico, with a Huichol shamaness. Nervous about yagé, he called taking psychedelics "going into 'The Mystery.'"

Andrew Doxer, a rail-thin teacher in a Boston after-school program, regularly visited a Mestizo shaman in Peru, to take yagé and fast. He wanted to follow the "shamanic path." The first time he drank the brew, Andrew said he saw a visible current of energy flow up into him from the floor. He realized, in a flash, that he should be working with children. After that, he stopped having visions, which was frustrating. Yet he was ready for another dose.

Our group also included Tamara Swingle, a cheerful twenty-three-year-old botany student from Washington State, small, blond, and muscular. John Emerson, a well-traveled beekeeper from Hawaii, looked like a spy from a Graham Green novel in his Panama hat and khaki suit. Jean Michel Taub, a French businessman, reminded me of Pepe Le Peu, the insufferable French skunk from Warner Bros. cartoons. While mocking American consumerism, Jean-Michel brought a handheld global-positioning device to the jungle. (He offered to explain its workings to Don Caesario: "No, thanks," the shaman replied gruffly. "I already know where I am.")

Almost instantly, our group started to succumb to the jungle conditions. On the second day, Tammy, seemingly the fittest of us all, caught a raging stomach bug. Hae Soog Jo, a Korean academic from Berkeley, developed a severe infection on her foot. A few others bumbled into a hive and were attacked by angry bees. The casualties crept back to their tents or hammocks, where they lay, dazed by the intense midday heat, making the rest of us feel lucky.