Fred Gilbert is a young fellow who has made something of a personal discovery - that the art of lute-playing as it was practiced during the heyday of the lute, in the Renaissance and Baroque periods, is today largely a lost art, and one that is in danger of being lost to the world forever. Listening to Gilbert recount the intricate history of the instrument whose sound filled the air in Shakespeare's day as the electric guitar does in our own, and listening of the delicate and vibrant sounds Gilbert brings forth from that instrument, one is quickly charmed.

Fred Gilbert is 24. He is compactly built, with a powerful chest and shoulders and a round stomach. He wears a blue T-shirt, jeans and Earth shoes, and his face is encircled by a shaggy corona of honey-colored hair. His small eyes are busy, as if holding the pilot flame of his enthusiasm. When he talks about the lute, these eyes dart repeteadly toward the sheets of music on the desk, and after a few minutes he says, "I'm going to pick up my lute, because I'm nervous" - which he does, and picks at it while he speaks of the history and present state of his art.

It was four years ago, when he was 18 and a student of the classical guitar, that Gilbert first became aware of the uniqueness of the lute. He'd become dissatified playing lute music that had been adapted for the guitar. Recordings he'd heard of the lute itself seemed to him to bypass the instrument's real potential, as originally played, by using modernized lutes and modern techniques of fingering. He realized, he says, that, "There must be ways of doing this, on the instrument, that separated it from the guitar." That year, Gilbert traveled to Europe to look for original manuscript and authentic instruments.

He discovered that libraries in Oxford, Paris and London were "packed" with lute music, dating from the 1600s, and written in archaic and often eccentric notations, most of which had not been played in modern times. He read treatises, also dust-covered and obscure, expounding on proper lute-playing technique, and he saw what is thought to be the only Renaissance lute still extent. Gilbert made copies of the scores and treatises, and taught himself to write in the original natations. ("A lot of people write it out sloppily, which is okay, but I figured that as long as I was going to go that far, I might as well do it right.") When he got home, he arranged to have a copy made of the Renaissance lute.

In 1976, Gilbert returned to Europe to study his instrument at the Royal Conservatory in the Hague, "which I quit," he says, with a little smile of embarassment, "largely because I couldn't learn anything from the lutanists there." The Dutch teachers seemed to him somewhat "laid back." "I like industry. I like to get into something . . . Money was always a problem, and I'd rather spend it on instruments than on school. Obviously there will be doors closed to me. But I was disillusioned . . . because the standard was so low - not a low standard, but such a standard of ignorance. I guess I cared more. I couldn't see sitting in a classroom when I needed to practice six hours a day."

Gilbert recalls his first trip to Europe, on a tour with a chorale group from his high school. In the audience when the group performed in Paris was world-famous music teacher Nadia Boulanger. After the performance, says Gilbert, Boulanger came to greet the chorus and, in a gesture that he feels to be somehow significant, went directly to him. "That was a great experience," he says. "It told me that somewhere in music I'd find my niche. I knew it would be in my hands."

After leaving the Conservatory, Gilbert went to Basel, which he made his home base for further research expeditions, to the library of King's College, Cambridge, to the British Museum, to Paris and Bologna and other continental cities. He uncovered more manuscripts and learned more about the history of his instrument.

When he talks about the history of his instrument.

When he talks about the 16th-century lute - the precise ways in which it was plucked (from the uncertain evidence of contemporary accounts), and constructed (when a Renaissance master wrote of "cat" gut strings, did he, in fact, mean "cattle"?) - Gilbert can barely repress the flow of his discoveries. Names of court musicians and craftsmen, in unpronounceable High German and Dutch, spill from his lips in a mild-mannered torrent.

"We have the makings of the type of lutanist they had back then," he says. "I feel it's absolutely necessary for the lutanist to know his instrument - to know how its constructed. I'm not saying you should know how to build one - but almost." He smiles.

Part scholar, part musician, Gilbert's chief aim is to assist in the rebirth - the renaissance - of a special kind of music. "Its not like I'm rebelling, it's like a different instrument, a different sound . . . I just wish that people would realize that there are different ways to play an instrument." And, like many musicians, frustrated in explaining his craft, Gilbert turns eagerly to demonstrate his meaning with a sprightly, densely noted Elizabeth dance tune.

Back in America since December, he's found few opportunities to play in public. "The only problem with the lute is that you're sort of a museum piece yourself. . . . It makes me think I belong in the Dresden collection. . . . My problem is being heard. People aren't interested."

Money is a further difficulty, to finance his research in Europe, and to live on while he progresses toward mastery of his instrument. ("I want to play historically - and well.") He is currently applying for a foundation grant.Part of his application is a set of three pieces of lute he's written himself, in a original Renaissance notation. He doubts his chances for success, though, since it's unlikely that the committee will be able to read his composition.

Being, at present, broke, Gilbert is living with his family in Vienna, Va. He keeps his two lutes, which are copies of graceful antique instruments, and his music - photo-copies of ornate antique manuscripts - in the basement study of a neighbor's home, where he ordinarily practices several hours each day. He plans to return to Europe in the fall (mention of the trip makes him smile), to unearth more forgotten music and, if thing work out, to give some recitals.

Reflecting on the itinerant start, and uncertain future, of his young career as an anachronistic voice in the music world, Fred Gilbert sometimes identifies himself with Elizabethan dramatist Kit Marlowe, whose rogue's life ended at the point of a sword.

"I've never really left my mark anywhere, and the only way I will is with my music. I think I'm going to burn out at an early age." He smiles. "But things have worked out for me - sometimes you want to quit, but I've gone too far. I can't do anything else. I guess I could be a mechanic (he's handy with cars) - but I'd want to play when I got home at night, and my hands. . . . "

A bulky figure in jeans and a T-shirt, delicately fingering his Venetian lute (a sculpture in Florentine cypress and Swiss Spruce), Gilbert speaks of the importance for culture of tradition, of preserving the unique achievements of a forgotten art.

He thinks he will someday return to school, to procure the degree that would "open doors," and talks about playing at weddings and embassy functions as a means of support. But his immediate thoughts are on his upcoming trip to Eastern Europe. Recalling the Allied bombing of Dresden in World War II, he worries about the possibility of another war.

"There are things in those museums that are not in Western libraries. There are two manuscripts - probably - in Prague. We've got to get these things out. . . . Sometimes I'm accused of living in the past. But I like to take the best of the past. . . . If it doesn't survive now it will die completely . . . I want my art to stand out."