The Laura Ingalls Wilder Medal is an American prize awarded to what type of book?

The Laura Ingalls Wilder Medal is a prize awarded by the American Library Association (ALA) to writers or illustrators of children's books published in the United States who have over a period of years made substantial and lasting contributions to children's literature. The bronze medal prize is named after its first winner, twentieth-century American author Laura Ingalls Wilder.

Originally, the Laura Ingalls Wilder Medal was awarded every five years, awarding six prizes between 1955 and 1980. From 1980 to 2001 it was awarded every three years, awarding seven prizes. From 2001 to 2015 it was awarded every two years. It is now awarded annually.