MARVELOUS MARKET -- 5035 Connecticut Ave. NW. 686-4040. Open: Tuesday through Friday 9 a.m. to 8 p.m., Saturday and Sunday 8 a.m. to 6 p.m. Closed Monday. Cash or personal check. Prices: one-pound breads $2.25 to $3.50, two-pound loaves $3.75 to $4.75, baguettes $1.25, ficelles $.90, brioches (available weekends only) $1 to $4.75.

HAVING FINISHED MY 28TH DIN-

ing guide and about to begin my 15th year of writing this column, I decided to break the routine this week. I'm not going to review a restaurant; I'm going to talk about bread.

Whatever else made San Francisco great, its sourdough played a part. Paris is the hub of the baguette, and would be a lesser city without it.

Now Washington has world-class bread. It's at Marvelous Market.

You should be suspicious of my making that statement, since that bread is being produced by a good friend of mine. Yet, after 14 years on this job, I hope I have built up enough credibility to compensate for that.

When Mark Furstenberg began talking about baking bread professionally, I was skeptical. I had been delighted by the food at his dinner parties and admired his homemade bread -- but as homemade bread, not commercial bread. I once brought him some bread from Paris to show him what I meant. He studied and experimented, and his bread grew better, but it was still far from a threat to Paris's Ganachaud or Poilane. Then he visited Los Angeles' La Brea Bakery, where Nancy Silverton -- formerly of Spago and Maxwell's Plum -- is making bread that is easily among the best in the world, so popular that the press has dubbed it "celebrity bread." Furstenberg watched her work, threw himself on her mercy and persuaded her to be the consultant for his bakery. He hired two bakers -- Stanley Bosefski, a foreman of a copper tubing company in Reading, Pa., and Gene Gathright, who had been making focaccia and pasta at

i Ricchi -- and sent them to La Brea Bakery for a month. Silverton trained them, shared her recipes and sent her head baker to Washington to oversee the bakery's start-up.

I was still skeptical until Furstenberg brought me his experimental bread shortly before he opened. Then I was amazed. It was the best local bread I'd tasted since Sam Weinberg closed Sam's Argentine Bakery and left for Israel in the '70s. And it wasn't even being made in the professional ovens yet. It now had that chewy, glutenous quality that makes great bread almost meaty, while its crust truly crackled.

Marvelous Market's bread, like the legendary Sam's, uses no commercial yeast. It begins with starter -- the fermented dough paste known as "sour" (as in sourdough) or levain -- which produces a more distinctive bread. Marvelous Market's starters grew from two cups each of white, rye and whole wheat starters Silverton created four years ago.

The flours also make a difference. They are specially ground by a small mill in North Carolina. And using Silverton's recipes makes the bread consistent from loaf to loaf. But of ultimate importance to the taste of these breads are the rising times.

Each day, some of each odiferous and near-liquid starter is mixed with flour and water to make a "sponge," then left for four hours to get the fermentation going. (In the case of white bread, following an ancient tradition, a piece of yesterday's dough -- called a "chef" -- is added to the sponge, intensifying the flavor.) The rest of the flour is added, and the dough is kneaded, then allowed to mature very slowly, mostly under refrigeration. This dough-making is a long process -- 14 hours for the white, 48 hours for the whole wheat with walnuts. Thus the flavor and the gluten develop far more than they would in the usual two-hour risings.

The bakery's French-made bread ovens hold the heat evenly and inject a powerful jet of steam so that a truly crunchy crust develops. And the bakers can control its thickness. In summer, for example, they make the crust of the baguettes extra thick to compensate for the softening effect of humidity.

Six days a week now, Marvelous Market is producing beautiful breads, slashed and puffed into well-browned and craggy boules, baguettes and little baguettes called ficelles. Inside they are skeined with glutenous strands and uneven bubbles, the texture as full of character as the flavor. Flat sheets of focaccia are sprinkled with parmesan or rosemary, or layered with taleggio cheese. White dough is studded with briny calamata olives, figs or rosemary. Whole wheat is combined with sunflower seeds and wheat berries. Rye is closely packed with currants -- though even Furstenberg admits that his plain rye bread isn't yet what we crave for our pastrami sandwiches. The array changes daily; on weekends there's brioche, and on Fridays a pretty good challah.

Breads are piled in baskets in the window for customers who like to pick their own, and on racks behind the counter for those who want the staff to do the choosing. There is no slicing machine -- these loaves are sold whole only. There are no plastic bags -- this bread should be left out to breathe. And Furstenberg recommends letting the breads sit uncovered -- cut side down -- so that the crusts remain crunchy. When they begin to grow stale after a couple of days they make extraordinary toast.

Marvelous Market sells more than bread. It stocks fine American cheeses, Bruce Aidells sausages from California, a few special jams, smoked fish and cured meats. But most important after the bread, Marvelous Market sells a changing and fascinating assortment of Sicilian carryout food made on the premises by Mimmetta LoMonte, a much-admired local cooking teacher and cookbook author. Hers are old-fashioned dishes from family recipes. For breakfast there is French toast to eat by hand. At lunch there are vegetable frittatas, and sandwiches on focaccia -- one vegetable and one meat -- and a dazzlingly good focaccia-based pizza topped with tomato slices, cheese and herbs. Each day, in time for dinner, there is a main dish or two, a vegetable such as broccoli with hot peppers and garlic or saute'ed spinach with sun-dried tomatoes, a polenta or pasta. Nothing costs more than $6 per portion. And while LoMonte has sometimes been too timid with her seasonings, and some dishes have shown too heavy a hand with the olive oil, I've seen her food steadily improve as she grows accustomed to large-quantity cooking.

Marvelous Market has become a neighborhood center where parents bring their children to pick their own baguette and people exchange reactions. "I can't believe you're here!" gushed one customer. "Decent bread in Washington -- did you think it was possible?" another asked the crowd at large. Within the first month, the store was regularly selling out each day.

Nothing can stop Washington now. It's finally got all the ingredients for gastronomic greatness.