Were the world's most expensive fungi served at the Last Supper?In villages across the south of France, truffles are a near-religious experience.

Frederic Lagrange

Unseasonably warm for January, by mid-morning it's approaching 50 degrees on Avenue de la Rabasse in Richerenches, in western Provence. The winter sun is blinding and the air is filled with the bold scent of the black truffle (or rabasse) for which the main drag of this fortified 12th-century town is named. Like scores of Provençal truffle markets held every Saturday from late November until mid-March, this one is teeming with buyers, sellers, wholesalers, and the occasional gawking tourist, who has come to see the humble beginnings of the vaunted truffle.

To me, the black truffle had always been a gastronomic caricature—a signifier of haute excess and all that is wrong with classic French cooking. It conjured images of Museum Food: overwrought offerings in shades of beige made from Continental "cookery books" with third-printing dates in the 1970's. This is not to say that as a wide-eyed food writer I didn't eagerly espouse all the self-important effluvia that my betters issued about its unique, nutty flavor with every plate of truffle-enhanced something-or-other I was served. I did.

Eventually, though, I broke through the propaganda and began to wave truffles off as I would the waiter's offer of "freshly ground pepper." Accepting either one at a restaurant, I believe, marks you as the kind of rube who can be talked into ordering whatever once-trendy bottle is now hogging valuable shelf space in the wine cellar. When it came to Tuber melanosporum, my heart was hard.

That is, until I met Hervé Poron. A nimble fellow with a quick, conspiratorial smile, Poron is a black-truffle wholesaler in the Provençal region of Vaucluse. Every year, he sells the best third of the 20,000-pound harvest fresh to top restaurants as far away as New York and San Francisco. The rest are canned—in industrial-sized cans, like those in school lunchrooms—for use year-round (fresh truffles last only two weeks). It is a powerful testament to the appeal of the black truffle that Poron's enthusiasm for it goes beyond the considerable money it earns him.

A meal with poron and his wife, Margaret, at their home on the edge of a grenache vineyard reminds me that the best way to enjoy the real gifts in life—truffles included—is simply and as soon as possible. On this January evening, at the peak of truffle season, I am welcomed with a big bowl of shaved truffles on the coffee table—presented the way Americans serve potato chips. As more guests arrive, we throw a piece of plywood over the dining room table to double its size, and graze on black truffles tossed in a salad and folded into omelettes.

At first light on Saturday, Poron and I are standing in sandy soil blanketed by oak twigs, acorns, leaves, and pebbles. This is Laurent Devilhet's farm. His Brittany spaniel, Polca, who has been trained to sniff out truffles, sits impassively at his side. Though there have been numerous advances in the seeding of hazel and oak groves (the truffle's native habitat), little has changed when it comes to the harvest. The most dramatic improvement has been trading the rooting pig, which has a natural affinity—verging on mania—for the truffle, for the scratching dog, who prefers a piece of sausage as its reward.

I have heard it said that if flies consistently gather above a spot in a grove in the warmer months, come harvest time the ground will yield a première truffe, or impressively large truffle, sometimes as big as a football. Likewise, it is believed that the moon governs truffle growth. The new moon lifts the truffle from its bed to about five inches below the surface, where its scent can be detected by a dog. If the moon really does lift the truffle in the earth as it lifts an ocean tide, the proof will offer itself here in a young white-oak grove, shortly after sunrise, a day after the full moon.

Devilhet palms a piece of sausage to Polca, and the spaniel is off like a shot, her tail motoring feverishly as she sniffs out truffles. By now, they've been hunting for four hours. Half-jogging to keep up, the farmer finally crouches at Polca's side; she seems to have found another one. Devilhet uses a hand pick to chip away at the hole Polca is digging. The truffle he brings up is the size of a large strawberry. He places it in a plastic box with the others gathered that morning. Later today, he will take his crop from the past week to the market.

In town, the fabled, knobby platanes (plane trees) are bare. they offer none of the shade that they were intended, when they were planted two centuries ago, to provide to horses and the carts they pulled. Today, where those trade carts once stood, a fleet of 20 modest station wagons (Renault 21's, Fiat Palio Weekends, Citro‘n 20Hdi's, Ford Escorts) are parked. Trunks are open, and the owners are ready for business.

At the height of the season, a market the size of the one in Richerenches, a town of about 700, can move one ton of truffles in a day. Here, the granite walls of the houses that line this avenue will reverberate with the sound of fevered commerce—black market commerce. The marché noir endures because the government in Paris considers the truffle a luxury item and levies a burdensome 5.5 percent sales tax on it. But the traders on Truffle Avenue ignore these regulations. There are no receipts here. Everybody pays in cash. Farmers make anywhere from 10 to 20 percent of their annual income at these markets; brokers make between $40,000 and $90,000 during the four-month season. And as they ply their quasi-legal trade, the local constables walk amiably (and apparently blindly) through the crowd.

On Saturday morning Truffle Avenue is quiet. Sellers sip from small glasses of espresso or cruise by the two dozen assembled brokers looking for a good price. The brokers lowball. Farmers get fed up. Tempers flare. Farmers retire to one of the town's two bars for a coffee or, more likely, a glass of wine or a Ricard, and grouse loudly to one another.

In the afternoon a seismic shift occurs. As though this were their first day at the truffle trade, the brokers suddenly realize that they haven't bought enough truffles to make their trip, from towns as far away as Avignon, worthwhile. They then start offering more money. This is the moment farmers have been waiting for. The sharp ones sell just as the price spikes, because as soon as the brokers are satisfied that they have enough in their bags (typically, gaily patterned pillowcases) to sell to wholesalers like my friend Poron, they suddenly drop their bids to nothing. Any farmers caught holding truffles once this wave passes must unload at a loss what they haven't yet sold. Deals are still made, but the spirit dissipates as the crowds move off Truffle Avenue. Many wander to the bars; some head directly home.

The spectacle of the harvest and the market have nothing on the pageantry of the Truffle Mass. Once a year, on the first Sunday after the 15th of January, the church in Richerenches holds a mass in celebration of St. Antoine, the patron saint of the truffler (well, of the farmer, really). It is one of the best-attended masses of the year; in the congregation are dozens of members of the Truffle Guild—growers, buyers, and brokers. Not unlike Shriners, they wear elaborate costumes: slouchy black hats and dramatic black capes adorned with broad yellow ribbons. The service is a confusing amalgam of scripture and commerce. Deftly applying some Gallic gastronomic topspin to his sermon, the priest suggests that maybe, just maybe, black truffles were served at the Last Supper.

After the mass, members of the Truffle Guild lead everyone to the Hôtel de Ville. Standing atop a rough-hewn table out front, the master of ceremonies—a walrus of a fellow, with some seniority in the guild—starts the auction. The Walrus performs a boisterous stand-up, waving various prodigious truffles about, selling the monsters singly and smaller specimens in pairs and trios to an enthusiastic crowd. The townspeople may act blasé, but they display a fair amount of energy. After all, this is one of the most important civic events of the year, and will raise money for the village. That becomes readily apparent when a tourist—a fancy lady from Paris or Avignon wearing weekend garb by Burberry, Persol shades, and Wellington boots—starts outbidding a local fellow sporting a Black Watch porkpie hat for an oversize truffle considered to be of particularly high quality. The crowd sees what is happening, lapses into a momentary silence, and then erupts in a rowdy chant resembling a British football fight song: "Richerenches! Richerenches! Richerenches!" Laughing, the locals raise plastic glasses of white wine and surge toward the auctioneer, egging on their neighbor to finalize his purchase. Cowed, he makes the winning bid ($1,000) and the truffle stays close at hand.

Standing here in the intersection, joking with Poron and the man in the porkpie hat, who wanders by, wincing as he ponders his titanic truffle, I find it hard to imagine how all the exuberance evaporates from the truffles as they make their way from the town square to restaurant plates. Luxuriant puffery replaces the playful hustle surrounding this delightful nutty fungus. The man in the porkpie hat hollers something we don't catch as gusts of the mistral pick up. Poron suggests we retire to the café for a glass of wine. "The show is over, no more truffles for now, okay?"

Manny Howard writes for the New York Times Magazine and Food & Wine.

Situated in western Provence, 37 miles from Avignon, Richerenches is most accessible by TGV from Paris to Avignon (nonstop in three hours) or by car from the Marseilles airport (about two hours). Stay at Mas de Grateloup (Rte. de la Coopérative de Villedieu, Buisson; 33-4/90-28-97-34; doubles from $55), a charming B&B in a neighboring town. Have lunch at Le Brin d'Olivier (4 Rue Ventoux, Vaison La Romaine; 33-4/90-28-74-79; lunch for two $36) and dinner at La Beaugravière (Hôtel Restaurant La Beaugravière, Mondragon; 33-4/90-40-82-54; truffle menu for two $124). For more information on the Truffle Mass, contact the mayor's office in Richerenches at 33-4/90-28-02-00.