Happy Labor Day to Nicholas Appert, Count von Rumford, Gustavus Swift, Clarence Birdseye and Margaret Rudkin, all of whom have made the art of entertaining an easier one.

When guests drop in and the cupboard is bare and dinner must be conceived from a can of this and a jar of that, it's time to say thank you to Nicholas Appert, who at the end of the 18th century, perfected the method of preserving by sealing food in glass bottles and boiling them.

His idea was later adapted to tins, and by the end of the 19th century canning had solved for many the problem of how to survive one more winter without running outside screaming, "I hate turnips!"

It is due to Count Rumford that the hostess does not collapse on the floor immediately after preparing the meal. Until he developed the closed-top range in 1795 -- with flues, dampers and metal plates to adjust heat flow -- women cooked over an open fire, using Dutch ovens and innumerable other -- mostly heavy -- gadgets to roast, broil or bake.

If the introduction of the wood-fed iron range did not offer the same ease as switching on a gas burner or an electric coil, it was nevertheless a vast improvement over the romance of the open hearth.

Gustavus W. Swift promoted the railway refrigerator car for shipping meat, making his first successful shipment of fresh meat from Chicago to the East Coast in 1877, thus allowing future generations to invite their friends over to grill a steak. Unfortunately, Swift is also the man who brought us oleomargarine.

Clarence Birdseye quit his job as a government naturalist to work as a fur trader in Labrador where, perhaps unavoidably, people froze much of their food for the winter. He began experimenting with freezing and by 1929 was marketing a line of quick-frozen foods that preserved much of the original flavor.

When next you are too tired to make dessert and settle for ice cream and a box of Pepperidge Farm cookies, think good thoughts about Margaret Rudkin, who founded the firm on the belief that store-bought bakery goods did not have to be dull.

And the next time you order Tarte Tatin, that turned-over apple tart, remember the story food writer Jane Grigson tells of how it came to be. The Tatin sisters had no oven and cooked their tarts on top of the stove, covered with a cone-shaped dome to hold in heat. The faster-cooking crust on the bottom would burn before the filling set. And so the sisters put the butter and sugar and apples in the bottom, where they would carmelize, and topped them with the crust which, away from the intense heat of the stove top, turned a flaky golden brown.

Cooked and upended, the rich amber tart is proof that one can always make a virtue of necessity.