"The Unquiet Library" is the slightly unsettling title of tonight's documentary on the music division of the Library of Congress (Channel 26 at 8). Volumes of musicology and priceless music manuscripts are part of the story and are given due attention. But they are only the beginning.

If producers Jackson Frost and Jeffrey Bieber had wanted to be even more dramatic, they might have called their show "The Schizophrenic Library." By any name, the thing that makes the music division telegenic is its radical departure from the popular stereotype of a library as a place where books lie around waiting for someone to pick them up.

Since the 1930s, the music division has had a series of activist leaders who thought of music not merely as something to be studied on paper but as something that people do and enjoy. Donald Leavitt, who recently retired as the division's chief, tells of a nightmare that afflicted one of his predecessors, Carl Engel: He was walking through the stacks and "hearing these notes on mute pages crying after him, 'Let us be heard.' " Since that nightmare, the Library of Congress has become one of the world's unique performing arts centers.

Engel and later music division chiefs, aided by private benefactors, have made the Library of Congress an instigator, an institution that not only preserves old music but also fosters the creation of new music and provides a space for free performances of the highest quality. As a result, "The Unquiet Library" not only shows a close-up of a technician meticulously removing traces of cellophane tape from the original manuscript of Gershwin's "Rhapsody in Blue." It is crammed full of lively clips: Appalachian fiddlers, blues singers, chamber music ensembles and even a melodramatic rescue scene from D.W. Griffith's epic "Way Down East."

One film clip shows Christopher Kendall conducting "Appalachian Spring," which (like many other modern masterpieces) was commissioned by the Library of Congress. Another shows Leadbelly singing "Goodnight Irene," one of the many treasures of Americana collected for the Library of Congress by Alan Lomax. "Banjo Dancing" star Stephen Wade is shown doing some fancy picking and talking enthusiastically about the riches of the library's folk music collection. And Joel Krosnick, cellist of the Juilliard Quartet, reminisces about his first encounter with the Stradivari cello in the library's collection -- "his" Strad when he is playing there.

Leavitt sums up the music division's dichotomous mystique: "This has been a curious job . . . for so many years I have had an awareness that we were serving two different publics. We had the scholars and students who came and used our reading room during the day, and then we had the people who came in the evening to hear concerts because they loved music."

During his tenure, Leavitt has enormously increased the acquisitions of what was already the world's largest music collection; he has accelerated and broadened the commissioning of new works and enormously increased the number of concerts in the Coolidge Auditorium. But his chief goal was to bridge the gap between the division's two publics through lectures, colloquia and the "Concerts From the Collections" series, which focuses on the incredible riches stored in the library's music collections.

Schizophrenia may be a chronic condition for an institution that is not only a library but a concert presenter, a publisher, a producer of radio broadcasts and a recording company. But it also makes "The Unquiet Library" a fast-paced blend of information and entertainment.