This award, established in 1936 in honor of Andrew Carnegie, is given for recognition of an outstanding book for children written in English and first published in the United Kingdom during the previous year. Note: Since 2007 the year relates to when the medal was awarded. Previously the year refers to the publication date of the books.
The official website can be found here
The LibraryThing award page for winners of the Carnegie Medal can be found here
and the LibraryThing award page for books shortlisted for the Carnegie Medal can be found here