The Royal Book of Oz is the fifteenth in the series of Oz books and the first by Ruth Plumly Thompson to be written after L Frank Baums death Although Baum was credited as the author it was written entirely by Thompson Beginning in the 1980s some editions have correctly credited Thompson although the cover of the 2001 edition by Dover Publications credits only Baum The original introduction claimed that the book was based on notes by Baum but th...