The Sir John Ritblat Gallery at the British Library houses one of the permanent exhibitions, Treasures of the British Library, and is free to the public. Libraries may seem dusty, stuffy places, but the Treasures exhibit pulls together over 250 of the more interesting items in the library's extensive collections.
Most of the items are documents or else related to books in some way. For example, Jane Austen's manuscript of Persuasion is displayed on the writing desk where she wrote it. Nearby, Mozart's marriage contract is displayed next to a manuscript for one of his horn concertos, and next to Virginia Woolf's manuscript of Mrs. Dalloway, you can pick up a pair of headphones and listen to her read an essay for BBC radio.
The items are arranged according to themes, among them literature, music, science, sacred texts and historical documents. Among the highlights are several of Leonardo da Vinci's studies; the Codex Sinaiticus and some original copies of the Book of Hebrews (written on papyrus); two copies of the Magna Carta; a copy of the Gutenberg Bible and dozens of illuminated manuscripts.
Special displays are devoted to Shakespeare and his Contemporaries, which displays a copy of Shakespeare's First Folio from 1623 along with original quartos of Romeo and Juliet and Shakespeare's will. In the Music section, many of the Beatles' original manuscripts are on display, and right now there is a special display case devoted to Samuel Johnson and his dictionary.
On entering the library, walk straight ahead and up a staircase. The Sir John Ritblat Gallery is on the left. It is signposted, but the doors are unobtrusive. If you find yourself in the café area, you've gone too far. A map of the exhibit is available from the information desk in the foyer.