THE LIBRARY'S HOLDINGS -- that would otherwise be closeted -- circulate in exhibits throughout the country.

The Library is running several concurrently here: IN THE JEFFERSON BUILDING

Hidden America: Suppressed, Censored and Privately Circulated Books -- A small but engaging glimpse into the collection. Upton Sinclair's "Oil! A Novel" was banned in Boston. Displayed here is his rare "Fig Leaf edition," where fig leaves cover the expurgated parts. When he sold copies of the edition on Boston Common, Sinclair was arrested. Other goodies: Roger Williams' "The Bloody Tenent" (1644), which was publicly burned, and Tom Paine's "Common Sense." In the Rare Book Room, second floor, through January. (Weekdays only.)

Books and Other Machines -- From a Macintosh computer to a tiny 18th-century hornbook to several incunabula (books produced before 1501), this show traces the development of books of all kinds. By using the motion-picture stills videodisk in this exhibit, you can call up movie titles from A to L and flip through their publicity photos. Fast-forward fun in the Great Hall, through June 2. Hours: Monday to Friday, 8:30 a.m. to 9:30 p.m.; Saturday to Sunday, 8:30 to 6.

Art Becomes the Poster: The American Art Poster, 1962- 84 -- Fifty selections from the more than 75,000 posters the Library owns. These are strong images depicting single subjects by Jasper Johns, Robert Motherwell, Alexander Calder, Georgia O'Keeffe, Larry Rivers, and the like. On the ground floor through April 28.

An American Renaissance: Toward a Multi-Media Encyclopedia -- Architects' plans and closeups of needed restoration -- of walls cracking, paint crackling -- show how much work lies in store for the Library of Congress as it begins its renovation of the Jefferson and Adams buildings this year. On the ground floor, indefinitely. IN THE JAMES MADISON BUILDING

The Realm of Folly: English Caricature From 1620 to the Present -- Thomas Rowlandson and James Gillray, from the golden age of caricature in the late 18th and early 19th centuries, vie with Gerald Scarfe and Sir David Low from the 20th century, and win. The 200 caricatures -- some bawdy, many bold -- demand a long perusal. You may have to visit them twice, in the first-floor exhibit hall, through February 17. Hours: Monday to Friday 8:30 a.m. to 9:30 p.m.; Saturday to Sunday, 8:30 to 6.

By Securing to Authors: Copyright, Commerce and Creativity in America -- We know what Barbie and Ken have in common. But what about Superman and Sam Spade? They're all represented in this permanent exhibit tracing landmark copyright cases. Their various mementoes, including the Maltese falcon from the movie of the same name, belong to the Library and are on view here. Along with an uncopyrightable hubcap, on the fourth floor near the Copyright Office. (Weekdays only.)