The Caldecott Medal was named in honor of nineteenth-century English illustrator Randolph Caldecott. Often called the father of the picture book, Randolph Caldecott (1846-1886) is regarded as one of the greatest and most influential illustrators in the field of children's literature. The medal is awarded annually by the Association for Library Service to Children, a division of the American Library Association, to the artist of the most distinguished American picture book for children.