Detective Notebook Secret Agent Codes Author:Chris Sasaki Top secret codes for super secret messages. — Spies could be hiding anywhere: at home, in your neighborhood, or even at school! Don't let your secret messages fall into the wrong hands. Send them in code to your fellow secret agents--trusted friends who can be counted on to keep things hush-hush. — Using your special Detective Notebook, you can le... more »arn all kinds of codes and then create messages with them.