A strange fate brings Princess Annabelle and her suitor Alexander to the Island of Knights and Knaves, where each inhabitant is either a Knight who always makes true statements, or a Knave who only makes false ones. They make friends with a sorcerer, who uses logic so cleverly that everyone thinks it is magic. Leading them through the complexities of logic, he takes them to a different island, where robots are programmed to make other robots with programmes of their own, and the reader has to work out what the programmes will be. The book ends with a guided tour of infinity, and we hear the remarkable story of how the devil was once outwitted by a student of the mathematician Georg Cantor. Raymond Smullyan is a mathematician and logician. He has also written The Lady or the Tiger?, Forever Undecided - a Puzzle Guide to Goedel, To Mock a Mockingbird, The Chess Mysteries of Sherlock Holmes and The Chess Mysteries of The Arabian Knights.