Corner cupboards for several centuries have had a lot going for them. For example: They help utilize every square inch of available space in a room, a factor as important in today's smaller homes as it was in one-room log cabins in Appalachia, in the homes of German settlers in rural Pennsylvania, or in Texas. In larger areas, such as the traditional dining room of a gracious colonial home , the use of two corner cupboards can provide a pleasing symmetry.
They don't take up a lot of needed wall space, but they do provide valuable storage for glass, cutlery, linens, and other household furnishings. Those with open shelves or with paneled glass doors at the top also form an excellent background to the display of favored dinnerware or pieces of fine porcelain. Both their own intrinsic design qualities and the objects they highlight often enable them to provide a focal point or a note of architectural interest to a room.
''Separate corner cupboards were known as far back as the William and Mary period (1626-50), and were referred to in American inventories in the 1720s,'' notes Helen Comstock in her now classic reference book, ''American Furniture'' (Viking Press, 1962).
In New England, paneled pine corner cupboards were being made in the period 1730-50. In the South, one walnut corner cupboard, made in two sections with arched panel doors and straight bracket feet, was made as early as 1750. Many were made in Texas and throughout the South from 1820 to 1870 in a variety of woods, including pine, poplar, and walnut. Styles ranged from simple, sturdy country pieces to those more intricately provincial, those more finely detailed by top cabinetmakers, and even some high-styled Federal versions.
During the Victorian era, corner cupboards declined in popularity. Glass-front china cabinets replaced them as display units.
Many antique corner cupboards are still available on the market, although each year they advance in price. The 14th edition of Kovels' Antiques List (New York: Crown) indicates that in 1982 an 18th-century Georgian pine corner cupboard sold for $4,200, a butternut Chippendale corner cupboard with raised panels for $3,000, a Pennsylvania corner cupboard with original blue paint for $ 3,600, and a 19th-century New York pine cupboard for $1,200.
William C. Ketchum Jr., author of ''Chests, Cupboards, Desks and Other Pieces ,'' from the Knopf Collectors' Guides to American Antiques, does offer one warning about buying antique pieces:
''The popularity of corner cupboards has made even the most ordinary examples expensive. As a result, brand new cupboards made of old boards are appearing on the market. Watch out for new paint, 20th-century nails, and boards with nail holes, as well as signs of artifical aging and wear in unusual places. All are clues that the piece is not what it seems to be.''
Today numerous corner cupboard reproductions, adaptations, and contemporary versions are being manufactured by top companies, including Drexel-Heritage, Thomasville, American Drew, Pulaski, and many others. Even relatively inexpensive ready-to-finish corner cupboards are available through stores and departments that specialize in unfinished furniture. Woodard even makes available a corner version of a small metal open-shelf baker's rack.
One California interior designer, in designing her own home, discovered that her tiny dining room had no wall long enough to accommodate a buffet. She was in desperate need of storage space. She solved the problem by buying three small-scale unpainted corner cupboards to suit their small English-type cottage. She and her children removed the heavy bonnets from the tops of the pieces, added their own molding trim, and sanded, stained, and waxed them. They put one cupboard in each of the three available corners of the small dining room, then used the bottom of each for putting things away and the tops for displaying assorted china and other family treasures.
Architect Charles Moore has even ventured to design for the ''Surface and Ornament'' international design competition a whimsical six-foot corner cupboard that is an art piece in itself. Its surface design of classical motifs is pure fantasy, worked in layers of Formica's new Colorcore surfacing material. Mr. Moore's ultra-modern transformation of the corner cupboard is now in the traveling exhibition of prize-winning original designs that were submitted by architects and designers.
Mary Ellisor Emmerling sums up the charm of the corner cupboard in her latest book, ''Collecting American Country'' (New York: Clarkson N. Potter). ''Corner cupboards were the mainstay of old colonial homes,'' she writes. ''They mixed utilitarian features with a decorative disposition. Corner cupboards monopolize those angles that might otherwise be considered wasted space. Further, they contribute to a room's character, just as recessed windows and rustic beams do. Because of their angled position, corner cupboards and their contents are visible from all vantage points, and thus are an integral part of a room's decoration.''