 Both books were intended as parts of a projected long-running fantasy series to replace the Oz books.Given the relatively tepid reception of the first book in the series, however, Baum tried to attract young readers by including two characters from his Oz mythos in "Sky Island"—Button-Bright and Polychrome, originally introduced in "The Road to Oz" (1909).The book was dedicated to the author's sister, Mary Louise Baum Brewster.