The Wizard of Oz is based on a book.
Dorothy Gale is the fictional main protagonist of many of the Oz novels by the American author L. Frank Baum . Dorothy first appears in Baum 's classic children 's novel The Wonderful Wizard of Oz and reappears in most of its sequels . The Wizard of Oz is a 1939 American musical fantasy comedy-drama film produced by Metro-Goldwyn-Mayer , and the best-known and most commercially successful adaptation based on the 1900 novel The Wonderful Wizard of Oz by L. Frank Baum .