L. Frank Baum 
The Marvelous Land of Oz [EPUB ebook] 

The first of many sequels to The Wonderful Wizard of Oz follows Tip, who is escaping from the sorceress Mombi. On his way to the Emerald City, hoping to start a new life, he creates Jack Pumpkinhead and the Wooden Sawhorse. Once the companions arrive in the Emerald City, they discover an army of girls have overthrown King Scarecrow. Joining with Scarecrow, they set off to find Tin Man, and ask Glinda for help setting things right. But first, Tip must find out who he is, they must defeat Mombi, and there is the small question of who rightfully should rule Oz…