"The Newbery Medal was named for eighteenth-century British bookseller John Newbery. It is awarded annually by the Association for Library Service to Children, a division of the American Library Association, to the author of the most distinguished contribution to American literature for children."
Source: http://www.ala.org/alsc/awardsgrants/bookmedia/newberymedal/newberymedal
The Newbery Medal is awarded annually by the American Library Association for the most distinguished American children's book published the previous year. (ALA)