Princess or Tiger? Mathematical Logic in Problems and Puzzles

How to find out in which room there is a beautiful princess, and in which - a fierce tiger? Is everything all right in the psychiatric hospital of Dr. Smoll and Professor Perrault? Is it possible to find out which of the inhabitants of the gloomy Transylvania is a terrible ghoul? The cunning inspector Craig from Scotland Yard is faced with such riddles almost daily and always successfully resolves them. But today the inspector is waiting for a particularly difficult task - you need to choose a cipher for an unusual castle of a locked safe. Realizing that one cannot cope, the inspector turns to friends for help: a specialist in mathematical logic and an eccentric inventor of digital encoding machines. Together they go on a fascinating journey through the waves of mathematical logic, making amazing discoveries