Ruth Plumly Thompson (1891-1976) was an American writer best known for continuing the Oz series of books created by L. Frank Baum. She was born in Philadelphia and began her career as a writer of children's stories in the 1910s. In 1917, she was asked by the publishers of the Oz series to continue the stories after Baum's death. She went on to write over 20 Oz books, including "The Royal Book of Oz," "Kabumpo in Oz," and "The Cowardly Lion of Oz." Thompson lived in Philadelphia for most of her life, but also spent time in California and Europe. She was married twice and had one son. She passed away in 1976 at the age of 85. Despite her significant contributions to the Oz series, Thompson is often overshadowed by Baum and his original books. However, her work has continued to be enjoyed by generations of children and Oz enthusiasts.