For the diplomats, detente may be as elusive as the unicorn, but on a commerce-cluttered Baltimore highway, the careless, crowded shelves of the Old World Delicatessen and Gift Shop offer a love feast from an undivided Europe.

Glistening red beads of Russian salmon caviar sit benignly in a refrigerated case with a look-alike, taste-alike caviar from Alaska. Polish Krakowska sausages repose temptingly near Black Forest bacon. And Dutch salt-herring marinates beside herring from the Baltic Sea prepared in the Russian low-salt schmaltz style.

On the grocery shelves, Italian pasta faces Rumanian preserves, while jars of Hungarian pickles mingle with containers of French Cornichons, and Yugoslav wafers with strawberry-nut fillings lie close to Austrian Bahlsen cookies. Bins of hard candy from around the globe form a veritable United Nations.

The uniqueness of the shop does not lie in any one product it keeps in stock -- though it might be hard to find such a treat as Kiev cake anywhere else in the Baltimore-Washington area. Rather, the attraction is that so many things from so many places are available under one roof in a congenial atmosphere.

The Old World sits in an unlikely spot in Randallstown, on Liberty Road, about 3 1/2 miles outside the Baltimore Beltway (I-695), past Popeye's and Pep Boys, McDonald's and the Burger King. Crammed into a squat brick building on a narrow lot between Midas Muffler and Shear Precision, the delicatessen presents an unpretentious front to the world, with only sketches of a globe and snow-capped mountains to suggest that there is something special about the party platters and carry-out sandwiches advertised in the window.

Yet people come from far and near to shop at the Old World, says the store's general manager, Gary Hein. Customers drive from Pennsylvania, Virginia and outlying Maryland, as well as Bethesda, Rockville and Gaithersburg, to fill their larders with European-type food.

Many of the customers are Europeans. But among the delicatessen's regulars are native-born Americans who in living or traveling abroad have acquired a taste for European staples and delicacies, or who simply have sophisticated palates and a yearning for adventuresome food. However, an American, on first coming to the Old World, might feel as if she (or he) had wandered into some border zone where the air is filled with a multiplicity of languages.

One reason some people will spend more than an hour to reach the Old World is that they know that everything is fresh, says Hein. Every Thursday he drives a truck to New York to hand pick perishables and to bring back a week's supply of imported items and European specialties that are now made there; delicacies such as a variety of hot-smoked and cold-smoked fish unequaled in Baltimore or Washington -- "everything from mackerel to sturgeon," says Hein -- or the unparalleled Kiev cake, a scrumptious melange of cake, meringue, cream filling and walnuts, said to have been a czarist favorite. The cakes seem to be customer favorites, too, and it is prudent to order them several days in advance.

Customers also come, according to Hein, because they find food processed in ways to which Europeans are accustomed -- without preservatives, coloring or other chemicals. All the cheeses, from the Danish havarti to an Italian ricotta pecorina, are white or the palest yellow. The only touch of orange in the cheese case is a small block of Velveeta, kept on hand not for mice, but for the casual patron who stops for a take-out sandwich accompanied, perhaps, by a bottle of Budweiser -- the only American beer in stock.

Hein claims the Old World's prices on comparable items are lower than those in metropolitan Washington because the cost of doing business in suburban Baltimore is much less. He points to a 500-gram (approximately 17 ounces) box of Belgian chocolate sea shells made by Guylian, which sells for $9.49. Belgian sea shells were a best seller everywhere in 1984, Hein says. In Washington, Chez Chocolat quotes a price of $13.99 for the same product.

The Old World is a "mom and sons" enterprise that grew quite naturally from the Hein family roots. Annie Hein, the mother, is from Germany. Her husband, Gustav, who was born in Lithuania and lived in Poland and Germany before coming to the United States, does not work in the store, but his knowledge of Lithuanian, Polish, German and English contributes to the family's linguistic virtuosity. He is a cabinetmaker who has fashioned furnishings for several Baltimore landmarks, including the recently completed Meyerhoff Symphony Hall. Their sons, Danny, who runs the delicatessen, and Gary, though American-born, have traveled in Europe and speak German and French in addition to their native English.

Among six employes who are not members of the family, several speak European languages, including Russian. Most customers whose English is poor know they can find someone at the Old World who will understand them, according to Gary Hein.

"We also communicate without words," he says. "If someone knows just a few words of English, we can usually figure out what they are trying to say."

The Old World began about 20 years ago in the family home when Annie Hein started to give knitting lessons there. The lessons grew into knitting clubs that met at members' homes, and gradually she began to sell her handmade items at German and Lithuanian festivals.

Eventually, the family supplemented Annie Hein's handwork with imports and started a gift shop and mail-order service. But almost as soon as the Heins opened their door with a stock of imported crystal, linen, wood carvings, music boxes and clocks, the country fell into a recession. The value of the dollar plummeted in Europe and, almost overnight, the low prices in their catalogue were made obsolete. Reasoning that in a poor economy, people would cut out household accessories before they would do without customary food, they went heavily into comestibles, making room beside the hand-painted beer mugs and tablecloths for imported beer, wine and candy. And Annie switched her handwork to perishable goods like Black Forest cake made with real whipped cream -- mostly to fill orders.

Today, the Old World is like a curiosity shop, bursting with an astonishing variety of goods in a minimum of space. In fact, the Heins plan to expand in July into the space next door, now occupied by Shear Precision, and add a French bakery. The establishment has become a kind of crossroads-of-Europe-general-store, where one can go in search of something special -- four kinds of Russian mineral water; the extract for making kvass, a fermented Russian beverage similar to beer; tins of fish from Russia that Soviet citizens can't buy; Iranian caviar; Prague cake (made in New York); several varieties of dark bread, including one that is made in Canada with natural Canadian spring water, and a sourdough starter from Germany; European cosmetics like the original Cologne or the German-made Nivea cream, which users swear contains something that is missing from the American-made product.

Or one can go on a journey of serendipity, certain of finding something unexpected, something not to be found at the local supermarket.

The Old World Delicatessen and Gift Shop is open Tuesday through Saturday, from 9 a.m. to 6 p.m. (Friday until 8), and Sunday from 11 to 4. The telephone number is 301-655-5157. It is located at 9118 Liberty Road (take exit 18 west from I-695) in Randallstown, Md.