The Folger Shakespeare Library opened a new exhibit this week, Extending the Book: The Art of Extra-Illustration, which explores “extra-illustration,” the practice of annotating a text with pictures of people and places who appear in the work.

The art form was especially popular in the 18th century, most notably in editions of Shakespeare’s plays, since there were plenty of characters (historical and fictional) and actors for artists to work with. To “extra-illustrate” a text, people added their own pages to a text with letters, maps, and artwork; these additions were a way for them to interpret and engage with the work.

On display are editions of Shakespeare’s plays, a letter by Mark Twain, a Eugène Delacroix watercolor, and a biography of Shakespearean actor David Garrick.

The exhibit runs through May 25, but don’t miss the virtual preview, complete with images, an audio tour, and other information.

EXTENDING THE BOOK IS ON DISPLAY AT THE FOLGER SHAKESPEARE LIBRARY, 201 EAST CAPITOL STREET SE, FREE, (202) 544-7077

Illustration: Pinkney Marcius-Simons. Watercolor and gouache paintings of A Midsummer Night’s Dream, 1908. Added directly to William Shakespeare’s Le songe d’une nuit d’été. Paris, 1886. Folger Shakespeare Library.