The lady or the tiger? - Raymond M Smullyan

"The Lady or the Tiger?" is a series of problems and paradoxes all compiled chiefly to entertain and related to important concepts of contemporary logic and mathematical theory. The puzzles range from the simplest "old chestnuts" to the most tantalizing complexities.;In the first half of the book, a range of imaginary characters - sane and insane vampires, psychiatrists, dreamers, hermits, kings, knights, and knaves - pose questions, giving just enough information to enable the reader to solve problems or increasing difficulty. A fair-minded king, for example, tells his prisoners the few facts necessary for a clever puzzler to earn his freedom (and perhaps a bride) by choosing correctly between the Lady or the Tiger. The last section, "The Mystery of the Monte Carlo", is a mathematical novel. Beginning with the practical problem of finding a combination to open a safe, Inspector Craig, serendipitiously assisted by two friends and their number machines, finds himself in ever deeper mathematical waters, which lead eventually to the very heart of Godel's revolutionary theory of undecidability.