Tired of having private information in your diary revealed? Annoyed when pesky ears listen in on private conversations? This book tells you all you need to know to set upknow to set up secret ways to communicate with your friends. With clear instructions and plenty of humor, the authors show you how to use everything from Pig Latin to Morse code to invisible ink to mystify enemy spies. A funny message is mixed in throughout the book, and if you get stumped the answers are in the back.