WASHINGTON, D.C. - As the Twentieth Century draws to a close, Edith Wharton - Victorian blueblood, Old New York chronicler, illuminator of forgotten manners, places and scenes on both sides of the Atlantic - has become, along with her friend Henry James, something of a revived literary and movie sensation.

Spurred by the 1975 publication of R.W.B. Lewis's superb biography of a then rather remote, somewhat neglected literary figure, our bookshelves have swelled with new editions of her work and reappraisals of her many gifts, including interior design. More recently, Hollywood has discovered the cinematic potential of her novels of social mores with The Age of Innocence, and The Buccaneers was featured on PBS's Masterpiece Theatre.

Insight into why Wharton's writings remain popular, and into the complex woman behind those writings, is offered by a superb exhibition, "Edith Wharton's World: Portraits and Places," on view at the National Portrait Gallery through January 25. Organized by Wharton authorities Eleanor Dwight and Viola Hopkins Winner, it explores the life and times of the celebrated author by means of 100 paintings, miniatures, photographs, books and memorabilia.

The show places Wharton (1862-1937) in the context of the sites, friends, acquaintances and activities of the trans-Atlantic society that provided fodder for her work. From these worlds emerged such memorable characters as Ethan Frome, Lily Bart in The House of Mirth, Elena Olenska in The Age of Innocence, and the American debutantes who invade England in The Buccaneers.

Edith Newbold Jones was born not only into New York's "old money," but "old society." Her family, which could trace its Dutch and English ancestors back 300 years, was part of the city's elite "Four Hundred."

Edith was privately educated, read widely in her father's "gentleman's library," and grew up amidst genteel surroundings as a prim and proper little lady. Later she recalled hating the ugliness of New York in the 1870s, that "cramped horizontal gridiron of a town without towers, porticoes, fountains or perspectives."

Among her social friends growing up was Eleanor Roosevelt's famously attractive mother, Anna Hall Roosevelt. As depicted in a watercolor-on-ivory miniature, it is understandable why male contemporaries called her "a queen" and "bowed before her charm."

Sumptuous paintings by William Merritt Chase of his fabulous studio in the Tenth Street Studio Building and by Childe Hassam of fashionable Washington Square offer glimpses into the ambience of New York in Wharton's childhood. They recall what author Louis Auchincloss has called "that quaint, mild, oddly pure brownstone world that has disappeared."

Among the volumes on view is a first edition of Wharton's Old New York (1924), a collection of four novels (reprinted by Scribner's in paperback in 1995), set in the Manhattan of her childhood. Several strike surprisingly modern themes.

Edith Jones's eyes were opened to the potential of the broader world during frequent youthful tours of Europe with her family. Portraits painted in London at the ages of eight and 19 suggest her development from poised little girl to intelligent teenager anxious to spread her wings.

In 1885, at the age of 23, she married family friend Edward ("Teddy") Wharton, an attractive, well-educated man of leisure from a similar social background. He seemed a suitable match, but lacked Edith's artistic and intellectual interests and ambition. It was an unhappy marriage.

With her husband, Wharton lived through the extravagant years of America's Gilded Age, ever observant of the inroads of the nouveau riche into their world of old money and old families. They lived in New York and summered in Newport, the great watering hole of the rich and fashionable.

Portraits of various Astors, Belmonts, Roosevelts and Vanderbilts, and photographs of Wharton residences reflect the personalities and places of this period. In her fiction, notably The House of Mirth (1905), she delineated the materialism and social snobbery of that affluent world.

Growing up in the high Victorian world of old New York, Wharton had been surrounded by dark, oppressive rooms crammed with velvet-covered tables and cluttered mantelpieces, jardinieres holding palms, and doors and windows swathed in drapery. Her antipathy to these excesses was elevated by her travels in Europe, where she was exposed to the beauty and old-established order of the Old World. French pavilions, Italian villas and English country houses helped form and inspire her design details.

A copy on display of The Decoration of Houses (1897), the seminal primer on interior decorating written by Wharton and Boston architect/designer Ogden Codman, Jr, (1863-1951), is a reminder of the novelist's pivotal role in shaping American tastes and how she helped launch the profession of interior designer. Appearing a century ago and still in print, it was her first published book.

She and Codman got together in the early 1890s when she hired him to remodel her "incurably ugly" summer house, Land's End, in Newport. Wharton found that Codman shared her dislike of the "sumptuary excesses" of Victorian clutter and agreed that interior decoration should be "simple and architectural."

They gradually drifted into writing the book, which to their surprise became a popular and highly influential decorating text. Indeed, it helped revolutionize America's thinking about how a room should be put together.

Detailing the development of classical design from the Renaissance to late Eighteenth Century Neoclassicism, Wharton and Codman sought to explain, rationalize, correct and order design taste. Offering both theory and practical advice about interior design, they contended that room decoration should be treated as a branch of architecture, with interior architectural elements as important as the exterior of a house. Arguing that interiors should be governed by classical canons of good taste - simplicity, proportion, fitness and balance - they provided 13 chapters with pragmatic applications of these principles in terms of architectural features and specific rooms.

"Edith Wharton was about strictness, simplicity, and discipline," top contemporary decorator Mario Buatta has observed. "The whole point of what she did was that she cleared out the Victorian bric-a-brac. She had a respect for the Old Order that we don't see today." Adds Buatta somewhat apologetically, "I'm afraid I'm not as disciplined as Wharton and Codman were. My work is much fussier and looser and more flowery and romantic."

Thanks to its timeless good advice, The Decoration of Houses remains an invaluable guide for both professional and amateur interior designers. "Today it remains must reading," Jura Koncius wrote recently in the Washington Post, "even if some of the refined edicts culled from French, Italian and English villas and chateaux seem out of step with the 1990s penchant for shabby chic and feng shui."

Because, as architectural historian Richard Guy Wilson has written, Wharton is "perhaps the most purely visual writer America has ever produced," a careful reading of The Decoration of Houses provides crucial insights into her writings. "Without an understanding of Edith Wharton's architectural enthusiasm, much of her fiction remains mute, only half understood," says Wilson.

Wharton's own houses reflected both her philosophy of style and her philosophy of life. The Mount, which she designed and had built in Lenox, Mass., in 1902, gave her an opportunity to implement her ideas about architecture, interior decoration and gardens.

Sited on a hillside, the 32-room mansion was modeled after an English country house. There were separate suites for Wharton and her husband, four guest rooms and nine servant bedrooms. The ground floor features a symmetrical, perfectly balanced dining room, living room and library sequence. Wharton had The Mount's Palladian staircase open onto carefully composed gardens, lawns and hemlock woods, with the Berkshire hills in the distance.

"What is evident at The Mount," says Pauline C. Metcalf, director of Edith Wharton Restoration (the nonprofit group charged with preserving the structure), "are the principles of design as outlined in The Decoration of Houses. Symmetry is everywhere."

For a decade Wharton lived, wrote, gardened and entertained in what she called "my first real home." The House of Mirth was penned in her upstairs bedroom and Henry James became her favorite house guest. "No one," said James, "fully knows our Edith who hasn't seen her in the act of creating a habitation for herself."

Wharton finally sold The Mount in 1912, when her husband's ill health "made the burden of the property too heavy."

A combination of exacting ambition, grandeur and appropriate design, The Mount survives, in the words of Michael Conforti, director of the Sterling and Francine Clark Art Institute in nearby Williamstown, as "one of the most sophisticated and creatively Francophile residences...built in this country at the turn of the century."

Tours of the house nowadays by Edith Wharton Restoration offer visual documentation of its graceful symmetry, sense of purpose and deftly controlled space. In the summer, The Mount for years has also been home to the acclaimed Shakespeare and Company, which presents plays.

Wharton's exposure to the New England country ambience around Lenox and her painful experiences with her husband, a philandering manic depressive, led to the writing of Ethan Frome (1922). That classic tale of an unhappy marriage evokes emotions as cold as the winter in which it is set.

While in residence at The Mount Wharton put the finishing touches on Italian Villas and Their Gardens (1904), in which she stressed that gardens should be carefully planned in concert with their houses and natural landscapes. That volume remains such a classic that tours continue to be mounted of places she discussed: terraced gardens on Lake Maggiore and stately properties on Lake Como and in the Veneto and Florence.

A tableau or room setting created for the exhibition by New York designer Charlotte Moss illustrates Wharton's "simple, uncluttered" style. The vignette features some of the 31 fabrics and wallcoverings produced nowadays by Schumacher & Company as the Edith Wharton Restoration Collection. They are sold only through interior designers, with a portion of the profits going to maintain The Mount. (For information and locations of showrooms, call 212/213-7900.)

A number of the Schumacher fabrics are similar to those used personally by Wharton or Codman, and the names of many of them refer to her homes or friends or characters from her novels. In addition to Neoclassical prints and velvets there is a Lily Bart brocade, a Neoclassical woven honoring the heroine of The House of Mirth, and Olenska damask, a sumptuous green fabric named after the leading figure in The Age of Innocence. The St Claire-le-Chateaux wall covering, with a classical arabesque pattern, bears the name of Wharton's winter home on the Mediterranean.

After years of annual sojourns in Europe, Wharton settled permanently in France in 1911 - first in Paris and later in its outskirts. A Camille Pissarro painting of the Louvre looming over the boat-filled Seine hints at the sense of historic beauty and architectural grandeur that drew the writer to the City of Light.

It was in Paris in 1908 that Wharton began her torrid, extra-marital affair with the charismatic and dashing American expatriate, Morton Fullerton, who appears in full mustachioed elegance in several photographs in the show.

A faded copy of her poem "Terminus" recalls a night of passionate lovemaking in London's Charing Cross Hotel. It tells of "The long secret night you gave me, my lover," as she enjoyed ecstasy in the dingy room. Wharton recalls "lying there hushed in your arms, as the waves of rapture receded." It is a side of the patrician author unknown until a few years ago.

Unfortunately, Fullerton turned out to be a cad, with a long history of erotic links to partners of both sexes. Wharton broke off the affair after three years, but remained a friend and counselor to her ex-lover in his career. She divorced stuffy Teddy Wharton in 1913.

Other portraits in the exhibition document friendships Wharton maintained in France, both among the wealthy and well-born, such as the Comptesse de Trobiand and Mrs Henry White, and with French and visiting American writers and artists. The latter ran the gamut from Andre Gide and Jean Cocteau (depicted by Diego Rivera) to Henry Adams, William Dean Howells (a bronze relief by Augustus Saint-Gaudens), James and Theodore Roosevelt. Later acquaintances included Bernard Berenson, F. Scott Fitzgerald and Sinclair Lewis.

A luscious watercolor of Venice by John Singer Sargent and a Maxfield Parrish painting of Rome recall Wharton's frequent visits to those historic cities.

Wharton was an American who felt more at home abroad, especially in France. In "French Ways and Their Meaning" (1919, and reissued this year), she paid homage to her adopted land and its national character.

Her deep love for France was manifested during World War I, when she spent four exhausting years in Paris organizing and running war charities and establishing refugee shelters and convalescent homes. On periodic visits to the French front (immortalized on the cover of a French humor magazine) she distributed medical supplies and gathered impressions for a series of fervent war essays that helped rally American support for the Allied cause. They were collected in Fighting France (1915), while in The Book of the Homeless (1916) she assembled an illustrated anthology of war writings by prominent authors and artists of the day.

As illustrated in photographs and paintings in the show, Wharton spent her last years in two beautiful French houses that bore her imprint: summers at Pavillon Colombe, a small but noble Eighteenth-Century estate in a small village just north of Paris, and winters at Sainte-Claire, in an old monastery at Hyeres, perched on a hill with a spectacular view of the Mediterranean. She wrote in peace at both places, producing about a volume a year, and enjoyed the stays of such glittering friends as Berenson and Kenneth Clark.

Finally acclaimed as the grande dame of American letters, Wharton received the Pulitzer Prize for fiction in 1921 for The Age of Innocence and was elected to the American Academy of Arts and Letters in 1930. She made her last visit to America in 1923 to receive an honorary degree from Yale, the first woman so honored by a major university.

Wharton continued to write until her death in France in 1937. In all, 44 of her books were published in her lifetime. Her long neglected grave in the Cimetiere des Gonards at Versailles has been cleaned up in recent years in the wake of the resurgence of interest in her.

Wharton fans should not miss this enlightening and rewarding exhibition, which closes at the National Portrait Gallery on January 25.