Culinary historians credit Catherine Medici, wife of France's Henry II, with introducing the fork into the world of western dining. John Montagu, Fourth Earl of Sandwich, earned his place in history by finding a way to forgo it.

The gambling earl, during a 24-hour stint at the gaming tables, couldn't be bothered with the social niceties, so he sustained himself by slapping slabs of beef between pieces of toast.

While worthier dignitaries and doers of daring deeds have disappeared in history, the name of the finger-lickin' earl is known to every schoolchild. True, one may not consciously contemplate that 18th-century gamester when demanding a peanut butter and jelly sandwich, or insisting that it must be white bread and not that dark stuff flecked with seeds. But the legacy of John Montagu is with us still and is the basis for one of the great post-Thanksgiving treats: the turkey sandwich.

There are many celebrants who, while admitting that the feast is a very fine thing, secretly prefer the after-feast, the late-night scuttle down to the darkened kitchen, the quick fumble in the refrigerator to emerge with a platter of leftover turkey.

By this time it has become not only a ritual but a rite, as chunks of white meat are cut into thin slices, the bread buttered and spread with mayonnaise, a bit of watercress or lettuce spread on one slice, the meat laid in overlapping pieces on the other.

There are those who mash a bit of cranberry sauce into the mayonnaise. There are those who eschew butter and mayonnaise and instead dribble just the right amount of gravy on the bread, so that it is moist but not mushy, before covering the slices with turkey.

But the innovative sandwich, like so many things that delight us, is something we rarely offer to friends when we entertain them. No, these are our secret treats, for pick-up lunches or dinner on the run. For friends, we produce a sit-down dinner, with bowls and platters set out and courses marching by in proper progression.

And yet a meal presented between two slices of bread, a meal where we forgo not only the fork but formality, is an ideal holiday entertainment.

In so many of the events of the season, the meal is an afterthought. There are carol singing get-togethers, tree trimmings, outdoor picnics where friends drive out to the country to cut their own holiday fir. And, of course, there are football games. All of these events are easier to enjoy if the meal which accompanies them is an informal, sandwich supper.

The problem with the sandwich, where entertaining is concerned, is not the idea, but the execution. Peanut butter and jelly on store-bought white bread is not a meal to offer outsiders. But other sandwiches are. Sandwiches cut into interesting shapes, spread with unusual fillings and arranged in creative fashion are fit for any guests.

A holiday staple in the South, ham biscuits that simply are very good biscuits with bits of ham baked inside, are one creative variant on the sandwich.

Now there is a new book out that lists many, many more: "Great Sandwiches," by Susan Costner (Crown, $24.95), will make even the stuffiest host concede that offering guests bites on bread might be a very good thing.

The traditional turkey sandwich gets an ethnic twist in Torta de Pavo, hard rolls that are cut in half and partially hollowed before being spread with butter or oil and crisped in the oven. They are then filled with a pepper puree, a layer of refried beans, shredded lettuce, turkey, salsa and sour cream.

It would be an ideal meal for Las Posadas, the Mexican celebration on Dec. 16, a reenactment of Mary and Joseph's search for an inn that ends with a party where guests try to break a gift-filled pinåata.

Would anyone invited to a tree-trimming party feel that they had been shortchanged if, instead of sitting down to dinner, they found that lobster rolls with lemon aioli and artichokes were set out on the sideboard, ready for them to eat when the star had topped the tree?

There are French toast sandwiches that could be wrapped in tinfoil and kept warm, to be eaten by carolers as they make their rounds, or taken on a tree-cutting picnic.

Fillings can be stuffed into pita bread pockets or into hollowed-out loaves of French bread. They can be spread on sweet breads or on buns. Sandwiches can be deep fried, like the famous Monte Cristo, and then cut up into bite-sized bits and used as appetizers. They can be doused with barbecue sauce or given a tangy bite with horseradish.

Costner not only presents an imaginative array of sandwiches, but recipes for a variety of sauces and breads to construct them with, as well.

Who would complain they'd been served a pedestrian meal if the hamburger was sitting on a homemade bun and the ketchup sauce was concocted in your kitchen?

It's not the sandwich that isn't fit for company, but the way we have treated it. As did the earl who gave it his name, we think of it as a shortcut, not as a meal in its own right. But when prepared in imaginative fashion, when offered up on your prettiest platter, surrounded by sauces and parsley, pickles and chips, the sandwich can be a meal that allows us to entertain during this festive season while keeping one hand free to trim the tree.