Lyman Frank Baum (1856 &– 1919) was an American author of children's books, best known for writing The Wonderful Wizard of Oz. He wrote thirteen novel sequels, nine other fantasy novels, and a host of other works, totalling 55 novels, 83 short stories, over 200 poems and an unknown number of scripts. L. Frank Baum (1856&– 1919) was an American author of children's books, best known for writing The Wonderful Wizard of Oz. He wrote 13 novel sequels, nine other fantasy novels, and a host of other works, totaling 55 novels, 83 short stories, more than 200 poems, and an unknown number of scripts.