The dazzlingly clever and always entertaining Raymond Smullyan takes an unorthodox approach to chess puzzles by treating them as mysteries--with Sherlock Holmes as guide and mentor. The key concept is retrograde analysis. Rather than figuring out how to achieve some end from a given arrangement of chess pieces, the game is to examine the board and deduce what has happened in the past: Which side is white? What were the previous moves? Prove that a promotion did or did not occur. Which piece has been replaced by a coin? These are just a few of the challenges Smullyan presents through the eyes of Holmes and Watson. He even manages about as passable an imitation of Sir Arthur Conan Doyle's style as can be expected from a tongue-in-cheek presentation. To enjoy these problems you need only know how chess pieces move. The first puzzles in the book teach all the concepts you need to know to decipher the later ones; the process prepares you to join Holmes in solving a baffling double murder--they keys to which reside in a series of devilishly clever puzzles. The chess game is afoot, and it's almost too much fun!