The Classified Information tip book was a collection of codes and secrets for different NES games. It was published inside Nintendo Power magazine's volume 12 in 1990.
In order to remove the book without damaging the magazine, the reader had to bend back the silver staples, gently pull the book out, then bend the staples back into place.
About the book
The 36-page book had the games divided up by the secrets and tips. The categories included Continue Codes, Select Stages, Extra Player Codes, Multiple 1-Ups, Special Maneuvers, Sound Tests, Surprises, Invincible Codes, Bonus Points, Password Patterns, Super Strategies, and Game Boy Tips.