Believe it or not, kids love reference books - especially when they're framed as forbidden knowledge. Do Not Open: An Encyclopedia of the World's Best-Kept Secrets by John Farndon appeals to irreverent kids who believe the adult world is filled with secrets just waiting to be uncovered. From Area 51 to Air Force One, Jack the Ripper to the Mona Lisa, the book spans the oddities and mysteries of the worlds of art, history, and science. Published by DK who is known for making every book a visual feast, the ample illustrations in Do Not Open are no exception. Recommended for kids aged 8-12. Find Do Not Open at your local book store or online here. There's also a companion website where, if they pass the retina scan, kids can print out a secret spy badge.