For centuries, Europe’s great rivers have stirred...

For centuries, Europe’s great rivers have stirred the imagination of artists and the exhortations of nationalists, and today they keep on rolling along as international boundaries and arteries of commerce and communication.

Wayfarers following their courses, however, discover a more romantic reality: gently undulating journeys through history and some of Europe’s most beautiful scenery.

From its beginning in the melting Alpine snows of Switzerland, the mighty Rhine flows 820 miles past castles and vineyards, cities and villages, to reach the sea by way of Holland. For 160 years, the spanking white ships of the KD German Rhine Line have covered most of that route.

Besides sailing between Basel and Rotterdam, KD’s 350 cruises a year venture into the Moselle, the Main and the Scheldt rivers on journeys that range from two to six days. In addition to the line’s notable first-class cruises, a series of more economical Europa-class sailings can be booked.

A six-day itinerary that visits five countries has been added this year for the Italia, departing on July 15 and Aug. 19 from the Swiss port of Basel north through France, Germany and Holland, sailing into the Dutch province of Zeeland and then to the Belgian city of Antwerp. Fares range from $880 to $980 per person. For details contact the Rhine Cruise Agency, 170 Hamilton Ave., White Plains, N.Y. 10601, phone (914) 948-3600, or 323 Geary St., Suite 619, San Francisco 94102, phone (415) 392-8817.

Salen Lindblad’s Argosy Tours division also offers Rhine cruises aboard the Rex Rheni. Call them at (800) 223-5688 or write 133 East 55th St., N.Y. 10022.

Down the Danube

The “beautiful blue Danube” varies from steel blue to dark gray to, on occasion, a muddy brown--”It’s blue when you’re in love,” one Viennese woman says--but it waltzes along through constantly changing scenery, past the vineyards of Austria and along the borders of Czechoslovakia and Hungary to Budapest, then on to Belgrade, Bucharest and the Black Sea.

The trim little Sofia from DER Tours--(800) 252-0606 in California, (800) 421-4343 outside California--offers seven-night cruises along the Danube priced from $947 to $1,740 per person, double occupancy, depending on the season. The yacht-like Donaustar from Argosy Tours provides a combination of river cruise and land package for 12 days priced from $1,290.

Meanwhile, Maxim Gorky (the river boat, not the writer) is waiting in the wings to take you cruising along the Volga River between Kazan and Volgograd, and then along the Don to Rostov-on-Don. The Aug. 13 tour from Argosy includes three days in Leningrad and four in Moscow, with gala dinners and theater performances on the schedule. Fares begin at $1,940.

Luxury hotel barges also ply Europe’s rivers, and for people who spend their working days in the stress lane and want to get away from the pressure, they may offer the perfect answer. While almost everyone promises get-away-from-it-all vacations, barge companies really deliver them, because once you’re afloat, you won’t hear the headlines or be paged for a long-distance call--there are no telephones, radios or TV sets on board. On the other hand, if you want to reach out and touch someone, you can hop off and place a call from towns and villages along the way and perhaps find a copy of the International Herald Tribune.

Life on a barge is as lighthearted as a floating house party with friends. Since cabins are often small and simple, sometimes with upper and lower berths, you spend most of your waking hours in the lounges or out on deck with fellow passengers, who may number as few as four or as many as 24.

Hardly anyone ever misses a meal because, as with all trips by water, food is one of the special attractions. Chefs purchase fresh fruits and vegetables in open-air markets, breads and croissants from the local bakers, fish, meats and cheeses from the best purveyors. Good regional wines are always included with lunch and dinner.

A new barge called the Shannon Princess from Horizon Cruises sails along Ireland’s River Shannon and the lake of Lough Derg to Limerick, Tipperary and County Clare. Passengers attend a medieval banquet in Galway and a sound-and-light presentation in 800-year-old St. Mary’s Cathedral in Limerick.

Fares for the three twin-bedded staterooms begin at $1,390 per person, double occupancy, with a $300 discount on certain sailings for travelers over 50; the two suites and the two single staterooms are slightly higher. All seven have private baths.

In Holland, a circle cruise out of Amsterdam aboard Floating Through Europe’s hotel barge Lys along the Amstel, Drecht and Vecht rivers covers castles, cheese markets and windmills; Belgium’s famous art cities of Ghent and Bruges are visited by the same company’s 10-passenger Juliana. Fares for seven-day programs begin at $1,445 per person, double occupancy.

Abercrombie & Kent’s Actief, which sleeps 12 passengers, cruises the River Thames between Eton and Oxford, stopping at Cliveden House, former home of Lady Astor. It also sails the Henley Regatta course and, for “The Wind in the Willows” fans, it takes close-up looks at the original Toad Hall (Mapledurham House) and Ratty’s Victorian boathouse. Cruises are priced from $730 to $960 for three days, $1,330 to $1,750 for six.

Horizon’s Barkis and Peggotty, twin barges that travel in tandem, cruise England’s rural East Anglia region between St. Ives and Bedford along the Great Ouse River, visiting Sandringham House (winter home of the Royal Family) and the university town of Cambridge. Fares begin at $1,180 per person, double occupancy, for the seven-day cruise, with an additional $400 single supplement.

Floating Through Europe’s tandem barges Beverly and Jean cruise the River Avon and the Cotswolds between Stratford-on-Avon and Tewkesbury, and the seven-day journey includes reserved seats for a performance of the Royal Shakespeare Co. and a visit to the Marquess of Hertford at Ragley Hall, his ancestral home. The cruises depart weekly through mid-October; fares range from $1,295 to $1,495.

For more information and other itineraries, contact Abercrombie & Kent (which incorporates Continental Waterways), 1420 Kensington Road, Oak Brook, Ill. 60521, phone (800) 323-7308; Floating Through Europe, 271 Madison Ave., New York 10016, phone (800) 221-3140, and Horizon Cruises, c/o Hemphill Harris, 16000 Ventura Blvd., Suite 200, Encino, Calif. 91436, phone (800) 252-2103 from California or (800) 421-0454 from out of state.

You can also arrange for furnished self-drive barges for holidays on the rivers and canals of Europe. The cost is around $600 a week for up to four people in late spring and early summer, $1,100 in high season (mid-July through August).