To quote a reader, ''If all you know of Oz comes from the movie musical then you owe it to yourself to read the book that inspired Hollywood.'' Learn about Dorothy and her friends in the first of thirteen volumes by L. Frank Baum. Book Excerpt e end of her nose, while she counted "One, two, three" in a solemn voice. At once the cap changed to a slate, on which was written in big, white chalk marks: "LET DOROTHY GO TO THE CITY OF EMERALDS" The little old woman took the slate from her nose, and having read the words on it, asked, "Is your name Dorothy, my dear?" "Yes," answered the child, looking up and drying her tears. "Then you must go to the City of Emeralds. Perhaps Oz will help you." "Where is this city?" asked Dorothy. "It is exactly in the center of the country, and is ruled by Oz, the Great Wizard I told you of." "Is he a good man?" inquired the girl anxiously. "He is a good Wizard. Whether he is a man or not I cannot tell, for I have never seen him." "How can I get there?" asked Dorothy. "You must walk. It is a long journey, through a country that is sometimes pleasant and sometimes dark and terrible. However, I will use all the magic arts I know of to keep you from harm.