Listen--do you want to know a secret? Then you've got to know the code, and this guide reveals what any youngster needs to know to become a secret agent kid. In a logical, easy-to-follow progression, it takes children from simple letter scrambling to more sophisticated systems that can baffle nosy adults. There's plenty of space to write, too, so that budding spies can practice and perfect their work before moving to the next level. There's the Pigpen...