Do you have a child who is fascinated by the world of spies and the intricate world of codes? What kinds of codes did our forefathers use? Could we still use them today? Has there ever been a code that no one could break? What codes did we use in World War II that were so very successful? Can you devise codes of your own to use with your friends? This book includes all sorts of codes and tells clearly how to create them yourself. And, yes, there is a recipe for invisible ink!