The Wishing Horse of Oz is the twenty-ninth in the series of Oz books created by L. Frank Baum and his successors, and the fifteenth written by Ruth Plumly Thompson. It was Illustrated by John R. Neill. This book marked the point at which Thompson had written more Oz books than Baum himself..
Ruth Plumly Thompson was an American writer of children's stories, best known for writing many novels placed in Oz, the fictional land of L. Frank Baum's classic children's novel The Wonderful Wizard of Oz and its sequels.