Southwestern is also America's oldest living indigenous cuisine, its origins predating Plymouth Rock and Jamestown. I wasn't especially looking for a history course when I arrived hot on the trail of blue corn, fire-roasted chiles, and mesquite-grilled meats. But the past was, I found, in every bite I savored in the Land of Enchantment.

To untangle this cuisine's origins start with the agrarian-based Pueblo Indians, who cultivated its foundational beans, squash, and corn. Next, consider the Spaniards, who came north with Cort&#eacute;s in the 1500s, introducing wheat and rice along with the tomato, tomatillo, and chile of the Mexican Indians. Then bring in the Anglo-Americans who, after the Indians and Spanish had a few centuries of melding their cooking, introduced more foodstuffs, including new varieties of produce.

If you're chatting with someone anthropologically correct, you'll be careful not to use the blanket term "Southwestern," as many do, but to distinguish its subsets and hybrids—border, Tex-Mex, Mexican, American Indian, and the latest incarnation, nueva latina, to name a few. And if you start out as unenlightened as I did, you'll expand your boundaries for Southwestern fare to include Texas, Arizona, Southern California, Baja, and parts of Colorado and Oklahoma.

But you won't go wrong starting in New Mexico, the country's largest producer and consumer of chiles. My gastronomical research, which would take me from Albuquerque to Taos, began in a bright, well-equipped classroom of the Santa Fe School of Cooking, in Santa Fe's Plaza Mercado.

Founded in 1989 by Susan Curtis, the school has led culinary tours around the state and has educated many professional and home cooks in traditional New Mexican and contemporary Southwestern. My instructor, Kathi Long, is a chef, consultant, food stylist, and cookbook author who has worked as a sous-chef at Manhattan's Arizona 206. Long's most apparent talent was an ability to cook in front of a class of 10 students, answer rapid-fire questions, and hold forth on the menu she prepared from scratch—enchiladas with green and red salsas, posole (a stew of Mayan/Aztec-style corn), and capirotada, a bread pudding made with Mexican chocolate and marsala-soaked cherries (Long admitted to bending tradition with this last).

Long opened the class saying, "New Mexican cuisine is terribly simple. It's based on one chile, the New Mexican [called the Anaheim in California], which is green when fresh, red when it ripens."

"Simple" did not apply to Long's indulgence of our curiosity over the next four hours about the piquant chile and a roster of seasonings in this boldly flavored cooking. She charred a chile pepper on a slotted stove-top grill to deepen its liveliness. Then she stirred honey and sherry vinegar into the hot salsas "to counter bitter notes and layer in flavor." In between, she gave us pearls of wisdom: Cultivated for a thousand years, the chile, of which there are more than 200 varieties, can be fresh, dried, or powdered. It's an excellent source of vitamins A and C, having twice the amount of C as citrus. Hatch, in southern New Mexico, is the hotbed of chile cultivation. (Later, former Bay Area chef Mark Miller would tell me that California-grown Anaheims "don't have the clarity, the high singular note" of chiles grown in Hatch.) But the best red chile, a fuller, softer one, is grown in Chimayo, north of Santa Fe. The devilish habanero, the serrano, and the jalape&#ntilde;o hit you right away, while "the red ancho is softer, with a dried-apricot flavor," Long said.

Although my class didn't participate in the cooking, we did handle ingredients. As Long peeled the blistered skin from a chile, we passed around two containers of dried chipotles, one batch wood smoked, the other tea smoked. She toasted coriander and cumin seeds in a skillet to release their perfume, then passed them under our noses in the molcajete (a Mexican stone mortar).

Top Spots if you can stand the heat All area codes are 505, unless otherwise noted. The cooking class I took, Traditional New Mexican I, was part of a lodging package at the stylish Inn on the Alameda, (800) 289-2122, a hotel with Old World ambience, including a large fireplace in the lobby. It's near Canyon Road, Santa Fe's artist row. Rooms start at $157, breakfast included. The Santa Fe School of Cooking, 983-4511, offers classes from $40 to $88, and its little market sells (and mails) a broad array of Southwestern ingredients, cookbooks, and equipment. It's walking distance from the inn and from the elegant Inn of the Anasazi, (800) 688-8100, where rooms start at $265. In Taos, I stayed at the comfortable, historic Taos Inn, 758-2233 (with its Doc Martin's restaurant, which I found to be mediocre). Rooms start around $60. Where to Eat Santa Fe For traditional New Mexican: Maria's, 983-7929; Tomasita's, 983-5721; The Shed, 982-9030. For more contemporary Southwestern: Caf&#eacute; Pasqual's, 983-9340; Plaza Caf&#eacute;, 982-1664. For upscale innovative Southwestern: La Casa Sena, 988-9232; Coyote Caf&#eacute; (and Cantina), 983-1615; Santacafe, 984-1788. For variations on Continental and Southwestern: The Compound (emphasis is Mediterranean), 982-4353; El Farol (Spanish), 983-9912; Geronimo's, 982-1500; The Old House (at Eldorado Hotel), 995-4530. Chimayo Leona's Restaurante, (888) 561-5569, www.leonasrestaurante.com. Espa&#ntilde;ola (on Highway 285/68 between Taos and Santa Fe): If you can stand a smoky, truck stop-style caf&#eacute;, you can get sopaipillas fluffy as pillows and a hearty posole at Dollie's, 753-3161. Taos Plenty of homey New Mexican eateries here, but for more sophisticated fare, try Joseph's Table, 751-4512, or Lambert's, 758-1009. Albuquerque A family place with creative traditional New Mexican is Los Cuates, 268-0974. For "if you're not sweating, you're not eating" places, try Monroe's, 242-1111, or Sadie's, 345-5339.

We encountered the pungent and the aromatic: chipotles in adobo (tomato sauce with garlic and onions); epazote, a Mexican herb also infused as a tea, that counters the flatulence caused by beans; Mexican oregano (sweeter than other types); safflower petals used for coloring; and chile caribe (crushed red chile).

The final sensory lesson came from a doughy mass—subtle in its earthiness, biblical in its sustenance—a palm-sized ball of masa harina (lime-soaked corn). Mixed with salt and warm water, it traveled from hand to nose before the real communion. Long's assistant placed lumps of the batter into a press, then onto a comal, a grill. One hot tortilla made the rounds, its steamy pockets bursting with the sweet native muskiness of corn.

Finally, we sat down to an impeccable repast served with wines produced in New Mexico (the country's oldest wine-growing region). After that, I was ready for my own field trip.

Over the next few days, I paced myself through Santa Fe's restaurants, finding this "simple" cuisine growing increasingly complex and harder to define. Was Southwestern the homey classics—tamales, carne adovada, chile rellenos—of places like Tomasita's, Maria's (which is justly famous for its margaritas), and The Shed? Or was it the more freely interpreted menus of such haunts as the Plaza Caf&#eacute;, a 1940s-style diner where cashews may accent an enchilada, or Pasqual's, where roasted poblanos are pureed with potato and cream into a velvety soup?

At the most upscale restaurants, I found even bolder interpretations. Asian spring rolls burst with nopales (cactus) and tomatillo salsa at chic Santacafe. At Casa Sena, an appetizer's component smoked salmon, escabeche (pickled vegetable), drizzle of habanero cream, and chiffonade of fresh mint all remained distinct and compatible. And at my favorite, the Anasazi, cilantro-crusted scallops in a red coulis were redolent of wood smoke.

Proffering one explanation for these wild deviations was Mark Miller, owner of the Coyote Caf&#eacute;. Basically, Miller says, he and other chefs "have fused peasant ingredients with classic European techniques," hence modern Southwestern and nueva latina.

Miller, who in 1979 opened the Fourth Street Bar & Grill in Berkeley only to move to Santa Fe in the late 1980s, undid many notions. "Southwestern is really a romantic idea," he says. "It doesn't exist in its pure form, as it did before mass agriculture." He cited, for example, piki bread, which is no longer made in the traditional way—by spreading blue corn batter soaked in juniper ash over a flat fire-heated stone.

To talk Southwestern with Miller, a former anthropology student, is truly to get a lesson in civilization. "Real Southwestern's complexity," he says, "derived not from the number of ingredients in a dish, but from the ingredient itself." For example, Native Americans used 269 wild herbs, cultivated 400 ingredients, cooked with some 300 varieties of corn, he says, all subtly different.

Miller allowed that Southwestern is still evolving. Thus consoled that I wasn't dining on just nostalgia, I drove north from Santa Fe through the spectacular high country where vineyards, orchards, and farms still thrive in the fertile valley split by the Rio Grande. Like millions of pilgrims before me, I stopped in Chimayo, not so much to visit the 19th-century Santuario with its purported Lourdes-style healing power, but to see Leona's, a tiny brown adobe restaurant under a catalpa tree in the church's parking lot.

Leona Medina-Tiede started her roadside stand in the late 1970s. Today, she is known around the world for the handmade tamales and flavored tortillas, chiles, and many Latino food ingredients she sells (and ships mail order). I savored the complexity of a simple burrito, then continued north through the Sangre de Cristo Mountains to Taos.

At Taos Pueblo, which has been continuously occupied by the Pueblo Indians for more than 2,000 years, I understood the difference between today's Southwestern cuisine and its romantic precursor. Crucita, an old woman, coaxed me into her woodstove-heated home and insisted I buy some of her fry bread, baked in her modern-day oven. Outside, under a bright shellacking of winter sun, the horno, a beehive-shaped adobe oven, stood empty and cold, a relic of the past that is on the pueblo's $5 tour.