Morning fog blanketed the trail rising out of Molinopampa, a village on the eastern flanks of the Andes in northern Peru. Both sides of the rutted path were lined with cloud forest vegetation: towering ferns and gnarled, moss-covered trees from which bromeliads swayed like silvery apparitions. In the distance, it was possible to make out rolling bogs stippled with low hummocks of grass. Molinopampa’s plank-sided houses gradually faded into the mist below.

I toiled up the track at the rear of a packtrain led by two Andean women, Sonia and Carmen, plus a boy brought along as their helper. They...

Two weeks later I returned to Huascayacu with a mestizo named Julio, hired to help carry my gear. Julio moved effortlessly over the muddy trail even though he was carrying a machete and shotgun in addition to a heavy bag. We arrived before noon and were welcomed by Tomás. After a meal at Tomás’s house, Julio solemnly collected his pay and slipped back into the forest in the direction of Atumplaya.

On that uncommonly sunny day, Huascayacu was a vision of civic order. Women returned from their fields straining against heavy baskets of manioc supported by tumplines that crossed their...

The period from January to April is usually the wettest time of the year in the Alto Mayo, and so it was in 1977. The rains, whose approaching roar could be heard through the forest long before arrival, lingered for days at a stretch. Women used short dry spells to provision their families with plantains and root crops. They returned from their gardens bent double under heavy baskets of tubers, often with a machete in one hand and the other wrapped around a sleeping baby tucked, chrysalislike, into a cotton sling. Men mostly stayed home to work on house hold...

Sorcery faded into the background for many weeks, overshadowed by attention to the rice fields and the demands of everyday life. As the rains diminished in May and June, hunting picked up. Men returned from the forest burdened with peccary, armadillo, game birds, and the occasional monkey. Huascayacu’s passionless flirtation with Christianity continued, sustained by prayer meetings on Sunday mornings.

Two young men, Jaime and Samuel, led services when Tomás was away. They read Bible passages and taught the congregation songs from the Wycliffe Bible Translators’ hymnal. They encouraged children to mime the lyrics by pointing to heaven or stamping...

Not long after dawn, loud chanting could be heard from the largest room of Utiját’s sprawling house in the community of Alto Naranjillo. The percussive refrain “Esáksaktú najágkita, esáksaktú najágkita” alternated with constantly changing verses. The chanter was Urucínta, Utiját’s wife. A weathered, gray-haired woman who had lost many of her teeth, Urucínta wore a patched dress that had faded to mixed shades of pink. She sat on a wooden stool holding a folded piece of banana leaf directly in front of her mouth as she chanted. The leaf cradled mashed gingerroot, used more widely as a medicine than as...

Genaro’s wife, Tumús, served beer as he and I chatted in his house one day. After weeks of biding my time, I finally got up the courage to ask whether he would tell me about his life and work as an iwishín, a healing shaman. “Would you be willing to talk about how you became a healer and what happens when you take yáji? I’d like to record your story,” I said. Genaro, a vigorous middle-aged man whose general appearance was indistinguishable from that of his mestizo neighbors, appraised me for a long moment over the bowl of beer, which...

Eighteen months after walking into an Awajún settlement for the first time, I made the punishing dry-season trip up the Río Huascayacu to interview people in Shimpiyacu and two neighboring communities. Margaret had returned to the United States for several months to visit her family and purchase supplies for the final weeks of fieldwork. I used the time to visit all of the Awajún communities of the Alto Mayo, mindful that after nearly two years in Peru my paltry research funds were dwindling rapidly.

Hiring a motorboat and boatman for the trip upriver was a necessary extravagance. The Río Huascayacu,...

The astonished reaction of my Awajún hosts toNational Geographicimages of unclothed Indians from the Brazilian Amazon speaks eloquently of the range of values and practices found in a region once seen as relatively uniform. A textbook on South American Indians, published in 1959 by Julian Steward and Louis Faron, describes South America’s rainforest Indians as having “a fairly homogeneous culture” and living as “simple village people.” A half century later, the picture looks radically different. We know, for instance, that communities located along the Amazon were, until shortly after European contact, densely populated and ruled by powerful chieftains...

Moyobamba, the capital of the Department of San Martín, had become nearly unrecognizable in the quarter century since I last walked its streets. As recently as the 1980s, Moyobamba was a sleepy place reminiscent of Macondo, the jungle town immortalized in Gabriel García Márquez’sOne Hundred Years of Solitude. But by 2012 its languorous tranquility had surrendered to the tumult of a colonization frontier. The population had grown nearly fivefold thanks to the arrival of colonists from elsewhere in Peru. Roughly paved streets sprawled in every direction, mirrored overhead by a tangle of utility lines. Convoys of motorcycles and motorized...

This book’s final chapters were drafted in surroundings that could hardly be more different from the world familiar to the Awajún. Framed by the window was a portrait of New England winter: trees stripped by October’s leaf drop, drifts sculpted by January’s winds, ornamental grasses desiccated and askew. Only the occasional chatter of chickadees or the squeak of boots on dry snow broke the boreal silence. In reflective moments, I have wondered why someone from such an austere place should be among those fated to document moments in the life of the Awajún, an exuberant people in an exuberant natural...