Night falls, the stars wink, and after an hour, Suelo tramps up the cliff, mimicking a raven's call—his salutation—a guttural, high-pitched caw. He's lanky and tan; yesterday he rebuilt the entrance to his cave, hauling huge rocks to make a staircase. His hands are black with dirt, and his hair, which is going gray, looks like a bird's nest, full of dust and twigs from scrambling in the underbrush on the canyon floor. Grinning, he presents the booty from one of his weekly rituals, scavenging on the streets of Moab: a wool hat and gloves, a winter jacket, and a white nylon belt, still wrapped in plastic, along with Carhartt pants and sandals, which he's wearing. He's also scrounged cans of tuna and turkey Spam and a honeycomb candle. All in all, a nice haul from the waste product of America. "You made it," he says. I hand him a bag of apples and a block of cheese I bought at the supermarket, but the gift suddenly seems meager.

Suelo lights the candle and stokes a fire in the stove, which is an old blackened tin, the kind that Christmas cookies might come in. It's hooked to a chain of soup cans segmented like a caterpillar and fitted to a hole in the rock. Soon smoke billows into the night and the cave is warm. I think of how John the Baptist survived on honey and locusts in the desert. Suelo, who keeps a copy of the Bible for bedtime reading, is satisfied with a few grasshoppers fried in his skillet.

HE WASN'T ALWAYS THIS WAY. SUELO graduated from the University of Colorado with a degree in anthropology, he thought about becoming a doctor, he held jobs, he had cash and a bank account. In 1987, after several years as an assistant lab technician in Colorado hospitals, he joined the Peace Corps and was posted to an Ecuadoran village high in the Andes. He was charged with monitoring the health of tribespeople in the area, teaching first aid and nutrition, and handing out medicine where needed; his proudest achievement was delivering three babies. The tribe had been getting richer for a decade, and during the two years he was there he watched as the villagers began to adopt the economics of modernity. They sold the food from their fields—quinoa, potatoes, corn, lentils—for cash, which they used to purchase things they didn't need, as Suelo describes it. They bought soda and white flour and refined sugar and noodles and big bags of MSG to flavor the starchy meals. They bought TVs. The more they spent, says Suelo, the more their health declined. He could measure the deterioration on his charts. "It looked," he says, "like money was impoverishing them."

The experience was transformative, but Suelo needed another decade to fashion his response. He moved to Moab and worked at a women's shelter for five years. He wanted to help people, but getting paid for it seemed dishonest—how real was help that demanded recompense? The answer lay, in part, in the Christianity of his childhood. In Suelo's nascent philosophy, following Jesus meant adopting the hard life prescribed in the Sermon on the Mount. "Giving up possessions, living beyond credit and debt," Suelo explains on his blog, "freely giving and freely taking, forgiving all debts, owing nobody a thing, living and walking without guilt . . . grudge [or] judgment." If grace was the goal, Suelo told himself, then it had to be grace in the classical sense, from the Latin gratia, meaning favor—and also, free.

By 1999, he was living in a Buddhist monastery in Thailand—he had saved just enough money for the flight. From there, he made his way to India, where he found himself in good company among the sadhus, the revered ascetics who go penniless for their gods. Numbering as many as 5 million, the sadhus can be found wandering roads and forests across the subcontinent, seeking enlightenment in self-abnegation. "I wanted to be a sadhu," Suelo says. "But what good would it do for me to be a sadhu in India? A true test of faith would be to return to one of the most materialistic, money-worshipping nations on earth and be a sadhu there. To be a vagabond in America, a bum, and make an art of it—the idea enchanted me."

THERE ISN'T ENOUGH SPACE IN SUELO'S cave for two, so I sleep in the open, at the edge of a hundred-foot cliff. No worries about animals, he says. Though mountain lions drink from the stream, and bobcats hunt rabbits under the cottonwoods, the worst he's experienced was a skunk that sprayed him in the face. Mice scurry over his body in the cave, and kissing bugs sometimes suck the blood from under his fingernails while he sleeps. He shrugs off these indignities. "After all, it's their cave too," he says. I hunker down near a nest of scorpions, which crawl up the canyon walls, ignoring me.

The morning ritual is simple and slow: a cup of sharp tea brewed from the needles of piñon and juniper trees, a swim in the cold emerald water where the creek pools in the red rock. Then, two naked cavemen lounging under the Utah sun. Around noon, we forage along the banks and under the cliffs, looking for the stuff of a stir-fry dinner. We find mustard plants among the rocks, the raw leaves as satisfying as cauliflower, and down in the cool of the creek—where Suelo gets his water and takes his baths (no soap for him) —we cull watercress in heads as big as supermarket lettuce, and on the bank we spot a lode of wild onions, with bulbs that pop clean from the soil. In leaner times, Suelo's gatherings include ants, grubs, termites, lizards, and roadkill. He recently found a deer, freshly run over, and carved it up and boiled it. "The best venison of my life," he says.

I tell him that living without money seems difficult. What about starvation? He's never gone without a meal (friends in Moab sometimes feed him). What about getting deadly ill? It happened once, after eating a cactus he misidentified—he vomited, fell into a delirium, thought he was dying, even wrote a note for those who would find his corpse. But he got better. That it's hard is exactly the point, he says. "Hardship is a good thing. We need the challenge. Our bodies need it. Our immune systems need it. My hardships are simple, right at hand—they're manageable." When I tell him about my rent back in New York—$2,400 a month—he shakes his head. What's left unsaid is that I'm here writing about him to make money, for a magazine that depends for its survival on the advertising revenue of conspicuous consumption. As he prepares a cooking fire, Suelo tells me that years ago he had a neighbor in the canyon, an alcoholic who lived in a cave bigger than his. The old man would pan for gold in the stream and net enough cash each month to buy the beer that kept him drunk. Suelo considers the riches of our own forage. "What if we saw gold for what it is?" he says meditatively. "Gold is pretty but virtually useless. Somebody decided it has worth, and everybody accepted this decision. The natives in the Americas thought Europeans were insane because of their lust for such a useless yellow substance."

He sautés the watercress, mustard leaves, and wild onions, mixing in fresh almonds he picked from a friend's orchard and ghee made from Dumpster-dived butter, and we eat out of his soot-caked pans. From the perch on the cliff, the life of the sadhu seems reasonable. But I don't want to live in a cave. I like indoor plumbing (Suelo squats). I like electricity. Still, there's an obvious beauty in the simplicity of subsistence. It's an un-American notion these days. We don't revere our ascetics, and we dismiss the idea that money could be some kind of consensual delusion. For most of us, it's as real as the next house payment. Suelo doesn't take public assistance or use food stamps, but he does survive in part on our reality, the discarded surfeit of the money system that he denounces—a system, as it happens, that recently looked like it was headed for the cliff.