The Purple Prince of Oz (1932) is the twenty-sixth of the Oz books created by L. Frank Baum and the twelfth written by Ruth Plumly Thompson. It was illustrated by John R. Neill.
While visiting the neighboring kingdom of Pumperdink, Prince Randy of the Purple Mountains criticizes the king's grapes, claiming they are sour. Randy is sentenced to be "dipped", but Kabumpo, the Elegant Elephant makes him his attendant instead. Later, the royal family disappears and Randy and Kabumpo must save the day.
This is the first of Thompson's Oz books to carry the entire story on characters of her own creation. The fearsome Jinnicky the Red Jinn from Jack Pumpkinhead of Oz returns as a much more pleasant companion to Randy.