The Lost Princess of Oz by L. Frank Baum
The Lost Princess of Oz is the eleventh Oz book written by L. Frank Baum. Published on June 5, 1917, it begins with the disappearance of Princess Ozma, the ruler of Oz and covers Dorothy and the Wizard's efforts to find her. The introduction to the book states that its inspiration was a letter a little girl had written to Baum: "I suppose if Ozma ever got hurt or losted, everybody would be sorry."
The book was dedicated to the author's newborn granddaughter Ozma Baum, child of his youngest son Kenneth Gage Baum.
Dorothy is up early to start the day and she is seeing to her friends in the Emerald City when she notices Ozma has not awakened yet. Dorothy goes into Ozma's chambers only to find she is not there. She is nowhere in the palace either. And not only is Ozma missing, but all the magical instruments in Oz that can be used to find her are also missing.
Dorothy, Glinda and the Wizard work together with several other friends to track down the magical instruments and find Ozma. We also are reunited with several old characters: Button-Bright, the Winkies, and Betsy. New characters we are introduced to include King Coco-Lorum, Cayke the Cookie Cook, Frogman, and Lavendar Bear.