The intrepid Professor William Waterman Sherman, the narrator-adventurer of the story, sets off alone to encircle the globe in his hot-air balloon. He is a retired arithmetic teacher, who is tired of forty years of spitballs and gum on his chair. He has not, however, lost either his sense of humor or his intellectual curiosity. The Professor is an eccentric individual, although a totally likable one. His desire to maintain solitude aboard his balloon is an eccentric urge that he never loses—at the end of the book he is ready to try once more. With quiet irony the author places the Professor in a society filled with eccentrics, among whom he seems comparatively ordinary. His own curiosity and flair for experimentation are reciprocated by the inventive islanders and their fabulous creations.

When Professor Sherman lands on Krakatoa, he finds himself in the...