The Caldecott Medal is awarded annually by the Association for Library Service to Children to the artist of the most distinguished American picture book for children. It was named after Randolph Caldecott, an English illustrator from the 1800s. A committee of librarians who work with children's books read hundreds of books each year to select the winner. The award, a bronze medal, has been given out since 1938. Past winners have used various mediums like watercolor, ink, and collage to illustrate stories without words or to help tell the story through pictures. Honor books are also recognized each year for outstanding illustration.