Have you daydreamed of being a secret agent? Blending historical tales of the British Secret Intelligence Service from over the years with a wide range of mind-twisting puzzles, this book will test your mental agility. Whether you have a linguistic flair, an instinct for technology, or good old common sense, pit your wits against some of the greatest minds of our time with ingenious brainteasers including secret languages, sabotage-themed brain bogglers, and hidden codes.