L. Frank Baum 
Oz Series Volume Four 
The Lost Princess of Oz, The Tin Woodman of Oz, The Magic of Oz, and Glinda of Oz

These four books in the classic children’s fantasy series follow the continuing adventures of Dorothy, the Wizard of Oz, and other beloved characters.The Lost Princess of Oz: When Princess Ozma disappears, Dorothy Gale and the Wizard of Oz set out to find her. Together with Dorothy’s friend Trot and the young boy Button-Bright, they find themselves in the dangerous land of the powerful Wizard Ugu.The Tin Woodman of Oz: This magical tale recounts how the Tin Woodman was turned into a tin man by the Wicked Witch of the East. It then follows him on a new adventure as he goes in search of his lost love, aided by his good friend the Scarecrow.  The Magic of Oz: When a boy named Kiki Aru discovers a magical word that only he can pronounce, his mischief wins him a villainous friend, Ruggedo the Nome. Now Dorothy, the Wizard, and the Cowardly Lion must stop Ruggedo from using Kiki’s magic to take over Oz.  Glinda of Oz: In the final book of the original Oz series, Dorothy and Princess Ozma set out to stop a war between two obscure tribes. But when they’re taken captive, it’s up to Glinda the Good to save the day—with a little help from the Wizard, the Scarecrow, the Cowardly Lion, and the Tin Woodman.