FOOD IS always part of the fun at the Folklife Festival, but this year, the Smithsonian Institution's annual extravaganza puts "Food Culture U.S.A." right on the masthead as one of the festival's four themes. In addition to the usual concessions, the festival, which begins Thursday and runs through June 27 and June 30 through July 4, will feature cooking exhibitions, educational exhibits and appearances by some of the most respected chefs from Washington and around the country. Guest curator Joan Nathan, popular cookbook author, TV chef and former Washington Post magazine columnist, hopes to draw attention to such issues as sustainable agriculture, the melding of tradition and innovation into American cooking, and corporate food cultures that emphasize social and environmental responsibility. (These are also topics Nathan is researching for her next book, "The New American Cooking," scheduled for release in October.)

For example, Berkeley, Calif., "green" chef Alice Waters, credited with giving impetus to the organic and local-foods movement, will re-create her "Edible Schoolyard," a communal garden that uses planting and cooking to develop students' life skills as well as appreciation of farmers, at the east end of the festival grounds on the Mall. A related exhibit on "Tradition and Adaptation" will highlight the new generation of small-scale farmers. Other tents will explore world spices, artisanal cheeses, kitchen tools, chocolate, tea, safe sanitary practices and even honey making.

Inn at Little Washington five-star chef Patrick O'Connell; Cajun cuisine pioneer Paul Prudhomme and New Orleans "Bam!"-meister Emeril Lagasse; all-American produce advocate and coast-to-coast chef Charlie Palmer; TV chefs Steve Raichlen and Lidia Bastianich; James Beard best Southwest chef award-winner Janos Wilder of Tuscon; "Silver Palate" author and Parade magazine writer Sheila Lukins; master sommelier Karen MacNeil; vegetarian cuisine guru Deborah Madison; Chef's Collaborative co-founder Nora Pouillon; and Washington faves Roberto Donna, Michel Richard, Jose Andres, Fabio Trabocchi, Kaz Okochi, Morou Ouattara, Eric Ziebold and Todd Gray are just a few of the chefs who will lead cooking demonstrations at the Kitchen Stage. Other industry leaders, such as Chipotle founder Steve Ells, "Sausage King" Bruce Aidell, Jean-Louis Palladin Foundation director Ann Brody Cove, Steve Demos of White Wave/Silk soy products and Niman Ranch's Bill Niman, will sit around a sort of kitchen table in the narrative tent to discuss food-related topics.

The Folklife Food Fest, as it might be called, will also highlight the rapidly expanding wine industry in the United States, with hands-on demonstrations (not tastings) of viniculture and grafting; discussions of traditional techniques terroir, that mysterious blend of nature and nurture; and climatic and agricultural factors.

This year's highlighted nation is Oman, and the concessionaire for that area is Mimi's Cafe of Dupont Circle, which will be serving such popular Middle Eastern dishes as beef and chicken kebabs with rice, hummus with pita and fettoush salad. Healthful American fare, including a grilled Alaskan salmon salad, grilled organic Italian chicken sausage, crispy teriyaki tofu and a veggie-fruit-sunflower seed salad with mango chutney vinaigrette, will be provided by the Clyde's group inside the Food Culture section. Next to that, Gaithersburg's El Carbonazo will offer marinated grilled Peruvian chicken and salad and yuca, grilled marinated flank steak with rice and salad, chicken breast sandwiches and Peruvian corn.

Inside the National Forest Service area, the Forest Cafe will supply buffalo burgers, smoked fish plates, wild rice soup, venison stew, bean soup and fry bread. That will be catered by Shalifoe Native Foods of Manistee, Mich., which provided the concessions for the opening of the National Museum of the American Indian. (The Forest Service area will have its own exhibition kitchen, so to speak: a "Dutch oven" pit for roasting game or fish in a covered metal box or pot over open fire.) The "Slow Roast" tent, at the east end near Waters's Edible Schoolyard, will examine a common thread of cooking styles: It will be manned at various times by the staff of El Patio of Rockville, barbecuing whole cows in the fashion of the asados, or festive parties; three-time Memphis in May pit barbecue champion Mike Mills of New York's Blue Smoke restaurant; a Middle Eastern lamb grill and even a church supper.

Festival exhibits are open daily 11 to 5:30, with concerts and dances until 9. For more information, call 202-633-1000.