Want to know a secret? Then youve got to crack the code! Future cryptanalysts can learn how to send top-secret messages to friends and fellow spies with this comprehensive spy science secret message kit. Write on special X-ray paper that can only be deciphered when wearing your decoder glasses. Create invisible messages with secret markers. Use a cool cipher wheel. And keep a Super Spy Journal with a secret code library for quick reference. Even more fun when two spies to play together communicate in up to nine different ways!