Pssst! Want to learn how to make and break secret messages like a real spy? Of course, you do! This practical field guide has everything kids need to know about the art (and science!) of concealment—ciphers, codebreaking techniques, and plenty of hands-on practice sessions to help you become a super-secret spy. Go undercover with your favorite Avengers, such as Iron Man, Thor, Captain America, and more. Avengers assemble! In this must-have for fans of The Avengers, you can how to write and decipher hidden messages.