The question most frequently asked by visitors to the Library of Congress is: Where are the books? The answer is: on the 532 miles of shelves located throughout the library's three buildings: the Thomas Jefferson, James Madison Memorial, and John Adams buildings. Established in 1800, "for the purchase of such books as may be necessary for the use of Congress," the library today serves the nation, with holdings for the visually impaired (for whom books are recorded on cassette and/or translated into Braille), research scholars, and college students -- and tourists. Its first collection of books was destroyed in 1814 when the British burned the Capitol (where the library was then housed) during the War of 1812. Thomas Jefferson then sold the institution his personal library of 6,487 books as a replacement, and this became the foundation of what would grow to become the world's largest library.

Today, the collection contains a mind-boggling 121 million items. Its buildings house more than 18 million catalogued books, 54 million manuscripts, 12 million prints and photographs, 2.5 million audio holdings (discs, tapes, talking books, and so on), more than 700,000 movies and videotapes, musical instruments from the 1700s, and the letters and papers of everyone from George Washington to Groucho Marx. The library offers a year-round program of free concerts, lectures, and poetry readings, and houses the Copyright Office.

Just as impressive as the scope of the library's holdings is its architecture. Most magnificent is the ornate Italian Renaissance-style Thomas Jefferson Building, which was erected between 1888 and 1897 to hold the burgeoning collection and establish America as a cultured nation with magnificent institutions equal to anything in Europe. Fifty-two painters and sculptors worked for 8 years on its interior. There are floor mosaics of Italian marble, allegorical paintings on the overhead vaults, more than 100 murals, and numerous ornamental cornucopias, ribbons, vines, and garlands within. The building's exterior has 42 granite sculptures and yards of bas-reliefs. Especially impressive are the exquisite marble Great Hall and the Main Reading Room, the latter under a 160-foot dome. Originally intended to hold the fruits of at least 150 years of collecting, the Jefferson Building was, in fact, filled up in a mere 13 years. It is now supplemented by the James Madison Memorial Building and the John Adams Building.

On permanent display in the Jefferson Building's Great Hall are several exhibits: The American Treasures of the Library of Congress rotates a selection of more than 200 of the rarest and most interesting items from the library's collection -- like Thomas Jefferson's rough draft of the Declaration of Independence with notations by Benjamin Franklin and John Adams in the margins, and the contents of Lincoln's pockets when he was assassinated. Across the Great Hall from the American Treasures exhibit is one that showcases the World Treasures of the Library of Congress. Its multimedia display of books, maps, videos, and illustrations invites visitors to examine artifacts from the library's vast international collections. Tucked away in a corner of the Jefferson Building is another permanent exhibit, the Bob Hope Gallery of American Entertainment, which presents on a rotating basis, film clips, memorabilia, and manuscript pages from a collection that the comedian donated to the library in 2000.

If you are waiting for your tour to start (see schedule below), take in the 12-minute orientation film in the Jefferson's visitors' theater or browse in its gift shop. Pick up a calendar of events when you visit. Concerts take place in the Jefferson Building's elegant Coolidge Auditorium. The concerts are free but require tickets, which you can obtain through Ticketmaster (tel. 800/551-7328 or 202/432-7328).

The Madison Building, across Independence Avenue from the Jefferson Building, at 10 Independence Ave. SE, offers interesting exhibits and features classic, rare, and unusual films in its Mary Pickford Theater. Find out more about the library's free film series by accessing the LOC website (www.loc.gov), clicking on "The Library Today," then scrolling down to find the postings for the free concert series and the free film series. The Madison Building also houses a cafeteria and the more formal Montpelier Room restaurant, both of which are open for lunch weekdays.

Anyone over high school age may use the library's collections, but first you must obtain a user card with your photo on it. Go to Reader Registration in Room LM 140 (street level of the Madison Bldg.) and present a driver's license or passport. Then head to the Information Desk in either the Jefferson or Madison buildings to find out about the research resources available to you and how to use them. Most likely, you will be directed to the Main Reading Room. All books must be used on-site.