Can you imagine the world without hollandaise sauce? What would eggs benedict be but two english muffins sitting on a plate feeling alienated and used by their poached egg partners? And where would a fudge sundae be without a rich chocolate sauce but just a bowl of vanilla ice cream?

Sauces transform dishes from the mundane to the extraordinary. They make food more interesting by adding different nuances of flavor. A sauce can disguise the negative and accentuate and complement the positive in food. They also frequently form a bond between the ingredients in a dish and pull it all together. We could live without sauces, but who would want to?

Man has sauced his food since ancient times. Garum, a pungent sauce made from fermented fish, was one of the earliest condiments used by the Romans. Other sauce seasonings included cumin, coriander, cardamom, honey and flower petals.

"In their earliest days" says culinary historian Barbara Wheaton, "the primary role of sauces was to spice up food. Sauces were eaten with boiled and roasted meat and fish which had a rather bland flavor. There is a common belief that sauces were used in ancient times to camouflage the flavor [that may have been past its prime], but in fact, I have found little evidence of that in my research."

Wheaton, author of "Savoring the Past: The French Kitchen and Table from 1300 to 1789" (1983, University of Pennsylvania Press), says one of the earliest sauces was mustard. "People would eat mustard with roast beef exactly as they do today."

"People did not generally use plates in the 13th century," says Wheaton. "They used something called 'trencher bread,' which is a type of stale bread baked expressly for this purpose, dried out for four days, and cut in slices. When diners sat down at a table to eat, they would have a slice of trencher bread at their place on the table instead of a plate. They would place meat and dry foods on the trencher bread and put their dabs of sauce on top. So the sauces during these times probably had to be a fairly thick consistency, so that they wouldn't run through the plate."

It is also true, according to Wheaton, that during the late 17th and all through the 18th century, there was an enormous variety of sauces being invented and used, but sauces did not begin to take on the importance that they have today until the 19th century.

It was in the late 18th century in France that the sauces known as the "grand" or "mother" sauces evolved and gave birth to the classic sauces as we know them. These sauces were: white sauce, brown sauce, espagnole, tomato, mayonnaise, and green sauce. From these six basic sauces have come a repertory of about 200 variations.

To establish an up-to-date organization of this family tree of sauces and to give an idea of their compositions, it seems wise to refer to "Mastering the Art of French Cooking" by Julia Child, Louisette Bertholle and Simone Beck (1961, Knopf), a book many consider to be the bible on the subject of French cooking. Volume one of "Mastering the Art" lists the French family of sauces as follows:White Sauces: These stem from two cousins, bechamel and veloute. Both use a flour and butter roux as a thickening agent. Bechamel is moistened with milk; veloute, with white stock made from poultry, veal or fish.Brown Sauces: For the brown sauces, the butter and flour roux is cooked slowly until it turns a nut brown. Then a brown stock made with browned veal bones is added. (In a classic espagnole sauce, one of the most time-consuming of brown sauces, the cooking time goes on for hours -- sometimes days.)Tomato Sauce: This sauce is -- as it says -- made with tomatoes, and assorted herbs and other seasonings.Egg Yolk and Butter Sauces: Hollandaise is the mother of this family.Egg Yolk and Oil Sauces: These are all the variations of mayonnaise.Oil and Vinegar Sauces: Vinaigrette -- french dressing -- heads the family.Flavored Butters: These include the hot butter sauces, and butters creamed with various herbs, seasonings or pure'es.

These basic sauces came to be considered the soul and foundation of classic French cuisine. They were used in restaurant kitchens all over the world as the base for all classic French sauces up until a movement known as "la nouvelle cuisine" began to sweep across Europe in the 1970s.

The basic sauces -- particularly the white, brown and espagnole -- require cooking a broth with bones and seasonings for hours -- even days -- in one pot. In the "nouvelle" approach, the cooking time has been reduced drastically. Many sauces are prepared from scratch using the cooking liquid from the food. Sauces are not thickened with a roux (a combination of flour and fat), but are reduced to a concentrated essence or thickened with potato starch. Lightness has become the trait that distinguishes nouvelle from classic sauces.

Anton Mosimann, mai tre chef de s cuisines (head chef) of The Dorchester hotel in London, was trained in Switzerland from the age of 15 as a classic chef, but today he is a leading exponent of the nouvelle style.

He "was quite comfortable" with that style until he went to Japan at the age of 23 as head chef of the Swiss Pavillion and was exposed to the lightened and esthetic components so basic to Japanese cooking. Now he cooks only in the nouvelle style, although he still uses the classical sauces without flour.

"We don't make a bechamel sauce anymore," says Mosimann. "I take a basic stock of the particular vegetables -- or whatever is being cooked -- reduce it down, add a bit of cream with an egg yolk and that's it. It serves the same purpose. So the basic, classical base has not changed as such, but we have refined it and made it lighter in texture and much more modern."

In the nine years that he has been working at The Dorchester, Mosimann has seen a great deal of change in the kitchen. When he first began working, they tuned out what he describes as "the old-fashioned cuisine." Since then, the kitchen has made a 180-degree change. Mosimann claims that the kitchen not only catered to the demand, but they helped create it.

"I think classical sauces -- as they were -- are gone forever," he says. "The nouvelle approach is here to stay. We may call it by a different name -- regional cooking, the new American cooking -- whatever, but the ideas are the same. But it is important for a young chef to learn all the classical sauces to prepare him for the modern approach," Mosimann says.

Jacques Pepin has also seen a number of changes in the kitchen since he first apprenticed as a French chef 34 years ago, but they are quite different from those of Mosimann. Pepin, who is the author of four French cookbooks (including "La Technique," "La Methode," and "Everyday Cooking with Jacques Pepin," an accompaniment to his PBS television cooking series), a teacher, and former personal chef to three French presidents, recalls the stocks and sauces he prepared when he was learning to be a chef.

He " started his apprenticeship in "a very good restaurant" in Lyons in the south of France, "but we never used a brown stock," Pepin says. "We only used chicken stock or white stock. And it was the same with most of the other restaurants in the area. It wasn't until I went to Paris that I first made a brown stock. And the sauces were short-term and we used many herbs -- exactly as we do today.

"Then all of a sudden," continues Pepin, "we had this so-called continental cooking -- which is the password of any type of bad cooking. Now, after all those heavy sauces and bad cooking, we're going back to what was being done in all the best restaurants. Everyone is saying 'It's new,' but it's not new, it's just a return to sensible cooking."

Pepin maintains that stocks may be essential for cooking in restaurants, but in the home, it is another story entirely. Even sauces, he suggests, in the home kitchen have a limited calling.

"Probably in the classic French cooking, sauces are important, but at home they aren't really as important," he says. "You work more with natural juices and the pan drippings. You don't really get into that many sauce preparations unless you get into stewing and braising and things like that."

Pepin has one stock recipe in his latest book, "Everyday Cooking with Jacques Pepin," but he does not use it even once in the entire book. He says the book stresses the type of cooking done in his home and that his mother ("who has a restaurant and is a wonderful cook") never prepared a demi-glace a sauce that has been reduced to a thick glaze in her life.

"You see, in a certain type of French restaurant, the cooking is very structured and that is the way I was trained; I have my stock-derived sauces," says Pepin. "My mother and aunt, who are both excellent cooks, did not go through the same kind of apprenticeship that I went through. Their kind of cooking is far less structured. So, say they might cook a little roast of veal, they would keep the juice left over from cooking and use it to make some type of sauce, in a sense it is exactly the same thing I might do with my classic training."

In structured cooking, "We would first brown the bones, then cook a stock, then reduce the stock to get a very concentrated taste," says Pepin. "At home, we wouldn't do that, but it is almost the same thing."

When cooking at home, Pepin confesses a preference for the simple sauce "au jus," that is, made with the cooking liquid of whatever is being cooked, reduced with a little bit of water.

"If I am cooking in a class and people have come to see this very famous chef, I can't do that," he says. "I have to make something a little more complex. So, if I am roasting a chicken, I will take the juice, eliminate the fat, add water to it, and reduce it to 2-3 tablespoons of glace de viande. Then it becomes thick and it transcends the level of a simple sauce. It becomes a glace, which is much stronger."

Then, he puts that to the side and takes "some chicken stock, reduce that with a little white wine, some mushrooms, leeks, and then I will thicken it slightly with a little buerre manie (an uncooked thickener made of flour and butter) or a roux," says Pepin. "I will then reduce it a little more, add some cream, a little cognac, and the sauce is then spooned onto the bottom of the plate. The retained glace de viande is dribbled on top, and the cooked chicken is arranged over that. It lets a little garnish and this is the dish that is known as 'Poule a Pavillon' (a dish named after the famed Le Pavillon restaurant in New York where Pepin worked as a chef)."

Pepin offered a few suggestions for home cooks in their sauce-making ventures:"Even at home, it is advisable to make a little white or brown stock. To do this, you simply take some bones usually veal , brown them if you are making a brown stock, place them in a pot with plenty of water, add a few seasonings, and let it boil. While it is cooking, the fat should constantly be removed. Then it should be strained, reduced, and then you can freeze it. This is a very good flavoring agent and a base for any kind of sauce. You can thicken it with a roux or you can reduce it, adding a little cream and butter. You can do so many things with it and it lifts ordinary food up to another level of sophistication." "For poached fish or fillets, particularly flat fish and rockfish that have a slightly nutty flavor but are very lean, a butter sauce goes nicely, especially one with a little white wine. Then you might add a little cream and reduce it." "For oily fish -- like mackerel and bluefish -- I prefer grilling or broiling them and the I would advise making a sauce that is slightly acidic -- like tomatoes -- and perhaps some fresh herbs."

Any one of the following selection of sauces would complement nicely meat, chicken, seafood, or the vast supply of fresh vegetables now available in the markets. JACQUES PEPIN'S MORNAY SAUCE (Makes about 1 1/2 cups) 2 tablespoons butter 2 tablespoons all-purpose flour 1 cup milk 1/2 teaspoon salt 1/4 teaspoon freshly gound white pepper 1 egg yolk 3 tablespoons grated swiss cheese or 1 1/2 tablespoons grated parmesan

Heat the butter in a heavy saucepan. Stir in the flour until smooth and cook, stirring constantly, until the mixture froths (about 2 minutes) without browning. Add the milk, whipping constantly with a wire whisk. Cook until it boils, whipping constantly. Stir in the seasonings, and continue on low heat for 2 to 3 minutes, stirring constantly with a wire whisk. Cool slightly, for 6 to 8 minutes, then add the egg yolk, beating very fast and hard. Fold in the cheese with a rubber spatula. Do not use a whip or the cheese will "string." Serve with eggs, fish, poultry, veal, vegetables, pastas, and hot hors d'oeuvres. From "A French Chef Cooks at Home" RICHARD OLNEY'S NANTAIS BUTTER SAUCE (BUERRE BLANC) (Makes 1 1/4 cups) 1/4 cup shallots (lightly measured -- not packed), finely chopped 1/4 cup wine vinegar 1/4 cup dry white wine Salt to taste 1/2 pound unsalted butter (or more), cut into tiny cubes

Combine the shallots, vinegar, wine, and salt in a small, heavy saucepan. Bring to a boil and reduce at a simmer until no more free liquid is in evidence -- only a heavy film of moist and slightly mushy shallots lining the bottom of the pan. (if working over a gas flame, use an asbestos pad during the reduction -- it will then be tempered by the heat). Remove the pan from the heat for half a minute or so -- long enough to cool it slightly. Regulate the heat to very low, add about about an ounce of the cut-up butter to the pan, and return it to the heat, whisking. Add more butter, approximately an ounce at a time (7 or 8 additions) as each addition begins to disappear, only a trace of solid butter in sight. As the last addition disappears into the sauce, remove the saucepan from the heat, continuing to whisk for a few seconds. The sauce is a rich, creamy emulsion -- not too thick but with a distinct, firm body. It is only warm and, to avoid loss of heat, is best served directly from the saucepan. If form dictates the use of a sauceboat, warm it first to the approximate temperature of the sauce -- no more. Serve with poached, baked, or broiled fish, shellfish, vegetables, and eggs. From "Simple French Food" BASIC HOLLANDAISE SAUCE (Makes about 1 cup) 3/4 cup unsalted butter 2 tablespoons water 3 egg yolks (from large eggs) Salt and freshly ground pepper to taste Juice of 1/2 lemon

Melt the butter and skim the froth from the surface. Place the water and egg yolks in a heavy, non-alumininum saucepan. (If a heavy saucepan is unavailable, place the saucepan over another pan containing a little boiling water.) Whisk the egg yolks, beating vigorously over low heat, until they are thick and foamy. Remove the mixture from the heat and add the melted butter, drop by drop, while whisking vigorously. The mixture will become quite thick as the butter is beaten into it. Add the salt, pepper, and lemon juice to taste. Serve warm with poached fish, vegetables and eggs. JULIA CHILD'S BEARNAISE SAUCE (Makes 1 1/2 cups) 1/4 cup wine vinegar 1/4 cup dry white wine or dry white vermouth 1 tablespoon shallots or scallions, minced 1 tablespoon fresh tarragon or 1 tablespoon dried tarragon, minced 1 teaspoon freshly ground black pepper Pinch of salt 3 egg yolks 2 tablespoons cold butter 1/2 to 2/3 cup butter, melted 2 tablespoons fresh tarragon or parsley, minced

Boil the vinegar, wine, shallots or scallions, herbs, and seasonings over moderate heat until the liquid has reduced to 2 tablespoons, Let it cool.

Beat the egg yolks in a saucepan until thick and sticky, about 1 minute. Strain in the vinegar mixture and beat. Add 1 tablespoon of cold butter, but do not beat it in. Then place the saucepan over very low heat or barely simmering water and stir the egg yolks with a wire whip until they slowly thicken into a smooth cream. This will take about 1 to 2 minutes. If they seem to be thickening too quickly, or even suggest a lumpy quality, immediately plunge the bottom of the pan in cold water, beating the egg yolks to cool them. Then continue beating over heat. The egg yolks have thickened enough when you can begin to see the bottom of the pan between strokes, and the mixture forms a light cream on the wires of the whisk.

Immediately remove from the heat and beat in the other tablespoon of cold butter, then the melted butter by droplets. Correct the seasoning and beat in the tarragon or parsley. Seve with steaks, boiled or fried fish, broiled chicken, and egg dishes. From "Mastering the Art of French Cooking" WOLFGANG PUCK'S DIJON MUSTARD SAUCE (Makes 1 1/4 cups) 1 cup dry white wine 3 shallots, chopped 1 tablespoon fresh tarragon, chopped 1/4 cup heavy cream 1/2 pound unsalted butter, cut into small pieces 2 tablespoons chives, minced 1 1/2 tablespoons dijon mustard 1/4 teaspoon salt Pinch of freshly ground white pepper Juice of 1/2 lemon

In a heavy non-aluminum saucepan, reduce the wine, shallots and tarragon until 2 tablespoons of liquid remain. Add the cream and reduce again until only 2 tablespoons remain. Slowly whisk in the butter, moving the pan on and off low heat and whisking constantly. Don't let the sauce boil. Strain the sauce through a fine-meshed strainer. Return the strained sauce to the pan and whisk in the chives and mustard. Add the salt, pepper and lemon juice to taste. Serve with poached or steamed shellfish, fish, or chicken. From "Modern French Cooking" BASIC FRENCH VINAIGRETTE (Makes 1 cup) 1 whole clove garlic, peeled 1 teaspoon dijon mustard 1/3 cup tarragon or wine vinegar 1/3 cup olive oil 1/3 cup safflower or corn oil 1 teaspoon salt 1/2 teaspoon freshly ground black pepper 2-3 tablespoons fresh herbs of choice, such as basil, tarragon, or parsley, minced (optional)

In a blender or a food processor fitted with a steel blade, pure'e the garlic and dijon mustard. Slowly add the vinegar while the machine is running to blend. Combine the two oils and slowly add in a thin stream while the machine is running. Add salt and pepper to taste. Add the minced fresh herbs, if desired. Serve with raw and cooked vegetables, or as a marinade.