The fifteenth volume in the Oz series and the first to be written following L. Frank Baum's passing is The Royal Book of Oz (1921). When Professor Woggle-bug informs the Scarecrow that he has no family, he becomes distraught and returns to the cornfield where Dorothy Gale discovered him to look for his "roots." He doesn't come back, so Dorothy and the Cowardly Lion go in search of him. They encounter Sir Hokus of Pokes, an aged knight. They also encounter the Comfortable Camel and the Doubtful Dromedary. They go on a number of strange experiences while looking for the Scarecrow.
In this book, the Scarecrow learns that he formerly lived as a person. He was the ruler of the Silver Islands, a nation made up of people that resemble Chinese people and situated far below the Munchkin area of Oz. The spirit of the changed Emperor entered the scarecrow's body when the farmer set him on the beanpole, bringing him to life.
The Yellow Knight of Oz has Sir Hokus, the Comfy Camel, and the Doubtful Dromedary as its main protagonists. Once at the Silver Islands, Dorothy and her group rescue the Scarecrow from the locals and take him back to the Emerald City. The Scarecrow makes the decision to go back to Oz and carry on with his carefree life there.
Lyman Frank Baum was an American writer best known for his children's books, especially The Wonderful Wizard of Oz and its sequels. He wrote 14 novels in the Oz series, plus 41 other novels, 83 short stories, above 200 poems, and at least 42 scripts. He made many attempts to lead his works to the stage and screen; the 1939 adaptation of the first Oz book became a milestone of 20th-century cinema. Baum was born on 15 May 1856, near Syracuse, New York. His father, Benjamin, was a rich oil businessman, and young Frank developed in comfort. As a young child Frank was teached at home with his kins, but at the age of 12 he was sent to study at Peekskill Military Academy. He followed a variety of careers varying from acting to newspaper reporting to theatrical management to writing plays. Baum married Maud Gage, daughter of Matilda Joslyn Gage, a famous women's suffrage campaigner. His famous works are Mother Goose, Father Goose, The Wonderful Wizard of Oz, The Life and Adventures of Santa Claus, The Master Key, etc. He made and headed The Oz Film Manufacturing Company in 1914. Baum expired on 6 May 1919 and was buried in Glendale, California.