LONG, LONG AGO on some islands far, far away, a great civilization rose and fell and rose again before finally being taken over by alien invaders. The shrines of its gods were sacked and abandoned, and the jungle crept in to claim the ruins.

The home of that ancient culture now is known as Indonesia. War, time and the tropical climate have obliterated its early history and literature -- only a single sheet of poetry remains from before the 15th-century Islamic takeover -- and have dispersed the surviving Hindu and Buddhist sculptures throughout the world.

Now a sense of the richness and vitality of ancient Indonesia has been recreated in an elegant exhibition opening Sunday at the National Gallery of Art. The show is a feast of bronze and stone statuary, gold and silver adornments and temple artifacts spanning the thousand years from the Bronze Age to the end of such art following the coming of Islam to the archipelago's three thousand islands.

Much of the mastery of Indonesia's great carvers is seen as through a glass darkly, because the volcanic stone used by most carvers is porous, so that moisture seeps through it and causes the surface to spall off. Yet in some cases loss of detail emphasizes the essential beauty of such masterpieces as a 9th-century statue of Nandisvara (a manifestation of the god Siva). Although the features are worn away, the facial expression is suggested by the graceful lines of the body and the gently imperious inclination of the head.

Much of the mystery of Indonesia's past is yielding to modern archaelogy, but still almost nothing is known of great kingdoms such as Taruma, mentioned only in a few vague inscriptions, most of which are less concerned with history than with maintaining temple tax exemptions.

And the central mystery remains: One of the world's largest complexes of buildings was constructed in the fertile heartlands of central Java between 730 and 930 A.D., then the entire region was rapidly deserted, long before Islam began to have an impact. Whole peoples seem to have moved east or west, and although they built new shrines, they never again reached such heights of energy and invention.

Invasion and vulcanism are among the hypotheses advanced to explain the abandonment, but the theories are built on such slender data that they can collapse from the discovery of a new inscription or the reinterpretation of a single line.

While the dominant influence on ancient Indonesian art was Indian, the indigenous artists shaped a unique new sensibility. So transformed was the imported iconography that in some cases it's impossible to tell whether a statue represents a Hindu or a Buddhist deity. "I see India everywhere, but I do not recognize it," said the Indian poet Tagore when he visited the islands in the 1920s.

Visitors to this exhibition will see genius everywhere, and they'll recognize it. THE SCULPTURE OF INDONESIA --

Sunday through Nov. 4 in the East Building, National Gallery of Art. Open 10 to 5 Monday through Saturday, 11 to 6 Sundays. Metro: Archives.