COUNTRY HOUSES constitute the "greatest contribution of the English to the art of living" according to a historian-consultant with Debrett's Peerage. Originally they were the estates of families -- including members of the nobility -- who were part of the British ruling class from the Middle Ages to the early 20th century, and these homes are more properly referred to today as the "stately homes."

Many of those elegant properties, symbols of a wealthy upper class that in modern times has felt the unkind cuts of changing sociopolitical fortunes and soaring taxes, still retain their beautiful architecture, authentic furnishings, extensive landscaping--and staggering operating costs. All stately homes open to the public charge admission to help defray expenses, but few accept paying guests. The term "country home," however, can also refer to a more modest residence (though sometimes containing as many as 20 rooms) still dating back to the 16th century or even earlier but owned by someone from the middle class--perhaps an executive or retired colonel who has the same need to augment his income.

Thus, in recent years there has been a proliferation of tour packages limited to small groups and other vacation offerings that include visits to, and often lodging at, English homes. They run the gamut from a budgeteer's dream, the informal and ubiquitous "Bed & Breakfast" designed originally for individual, independent travelers that has now spread across the United States, to a pricey package titled "Live Like a Lord" that provides entree into the exclusive world of the titled.

Some tours are by motorcoach and escorted, others are self-drive. They may focus primarily on small country inns. Some mix homes and hotels. The B & B, which in London could be only an apartment, may become, in the country, an ancient farmhouse or impressive manor house. The country home usually has room only for a few guests and therefore can accommodate a tour package only when the group is limited in size and a sufficient number of suitable homes in areas to be visited are booked jointly by the tour operator.

All structures share a proximity to centuries of British history; though Americans will not find any place where George Washington slept--G.W. caught smallpox on a trip to Barbados and never again ventured outside his country--they may very well stay at a king's hunting lodge or a home with a deed signed by Charles Dickens.

And though cost-versus-value is something that concerns most tourists, and each brochure and description should be studied carefully with personal needs in mind, the feature that draws most Anglophiles is the chance to meet the British at home and sample briefly their way of life.

As one couple described their experience: "There is no way, as travelers, we could have purchased the kind of memories we have brought home. What you have given us is infinitely more."

Here is a selection of some of the tours currently available. In most cases they can be booked through U.S. travel agents (where prices are quoted in pounds, a pound is worth approximately $1.55 but it is necessary to check the latest exchange rate):

"ENGLISH HOMES & COUNTRY TOURS": Now in its fourth year, the 14-day trips were "set up to provide a unique cultural and social experience." The keynotes are "small, personal, intimate and stylish"; guests stay with British families and "see a side of life in rural England and Scotland which is normally inaccessible to overseas visitors."

Each group consists of 20 to 30 people (the English hosts usually accept only two guests and not more than four, Scottish hosts accept up to six). They are driven to stately homes, manor houses, cathedrals, medieval churches, castles and towns. Hosts and hostesses "include baronets, generals, doctors, company directors, members of Parliament" whose homes range from mansions to country cottages.

Where possible, tour members will dine in historic or other country houses and attend festivals and concerts. The three areas covered, with departure dates, are: Chichester, Canterbury and Cambridge in Southeast England (May 25); The Cotswolds, Bath and Exeter in Southwest England (May 18, July 13); Edinburgh, Perth and the Highlands in Scotland (July 13, Aug 31). Other dates may be added.

Cost (includes all accommodations and meals, except four meals in London and one meal in Edinburgh; drinks at homes of hostesses and at meals; all sightseeing and special events; tour director; travel insurance; all land transportation in Great Britain--but not air fare; taxes and tips): each English tour-- 965 £ per person in twin-bedded room; Scottish tour-- 985 £ per person double. Single supplement on all tours, 20. Address: English Homes & Country Tours, Coombe House, Sharnden, Mayfield, East Sussex TN20 6QA, England.

"THE BRITISH COUNTRY HOUSE": This series of programs has been planned by Abercrombie & Kent International Inc., in association with Debrett's Peerage, The British Tourist Authority and British Airways.

The intent is "to recreate the heyday of the Country House and give people the opportunity to live in the style of a bygone age. This has become possible because in the last eight years there has been a growing revolution in the country hotels and cuisine in Britain.

"A new style of hotel, the 'Country House Hotel,' has sprung up." Hotel and restaurant critic Egon Ronay describes them as usually "imposing country mansions, transformed by dedicated owners, often husband-and-wife teams, with unerring taste for attractive interiors and a true understanding of the essence of service . . ."

The tour operator has selected 23 properties in England and Scotland for self-drive and chauffeur-driven tours ranging from 10 to 21 days, which are flexible as to itineraries and departure dates according to client needs. There are also two itineraries with fixed dates, "The English Country House Revisited" and "The Castles and Palaces of Scotland"; guests will be escorted "by a lecturer especially chosen by Debrett's" and the group will be limited to a maximum of 20. "Just think of the burning log fires, fresh cut flowers, family portraits, four posters, antique furnishings, wonderful meals, wines and ports," tempts A & K.

Costs vary according to the package and are exclusive of air fares. A 10-day self-drive tour, using a Ford Fiesta, with superior room and full English breakfast, is $1,059 per person double occupancy. The 17-day English tour escorted by Debrett's lecturer, with all meals except in London, runs $3,847 per person double occupancy. Abercrombie & Kent International, 1000 Oak Brook Road, Oak Brook, Ill. 60521 (312-887-7766).

"COUNTRY HOMES AND CASTLES OF GREAT BRITAIN": Facilities are offered by ". . . no less than 100 distinguished families in England, Scotland, Ireland and Wales who open their doors to visitors each year," notes R & I Tours Ltd. in describing its program. The homes are divided into three categories: Grade A--stately homes and castles in extensive parkland; Grade B--country mansions and castles; Grade C--country houses and cottages.

Prices (Grade A, 170 £; Grade B, 115 £; Grade C, 90 £) are "per couple per night and include cocktails, three-course dinner with wine, coffee and liqueurs, overnight accommodation, full English breakfast"--and sometimes private facilities such as tennis, swimming, riding, hunting or fishing. R & I Tours, 138A Piccadilly, London W1V 9FH.

"LIVE LIKE A LORD": There are four holidays of 14 days in Britain, "three based in England; and for the first time, one based upon the castles and splendor of Scotland and Northern England." Guests stay at "stately homes and prestigious hotels," tour estates, and visit Ladies Day at Ascot, the Wimbledon Lawn Tennis tournament or the Henley Royal Regatta (depending on departure date). You can enjoy dinner at Longleat House, home of the Marquess of Bath--"in the Green Library, one of the private apartments not open to the general public," and a member of the Marquess' family will dine with your group.

On the Scottish tour, "you will reside in one of Scotland's best-known country houses, Glen House," which resembles a castle and has more than 10,000 acres of grounds. "You are invited to take over the house completely."

Cost per person double occupancy for each holiday, exclusive of air fare but including land transportation, all meals (except where specified) and predinner drinks and wine, theater and other admission charges, plus local taxes: $4,950 (subject to change). Jan Morris and Associates Ltd., Weston House, West Bar Green, Sheffield, South Yorkshire, England S1 2DA.

For information on additional packages, contact your travel agent or the British Tourist Authority, 680 Fifth Ave., New York, N.Y. 10019 (212) 581-4708. The BTA can also provide help in locating B & Bs (some rates are now as low as $10 a night per person; others, while higher, include dinner as well as breakfast and include private homes of higher quality).