I SPY BOOK

 One of the most interesting books for kids... 

I SPY BOOK challenge kids with regards to being sharp, how their mind works, finding clues and how sharp is their vision to find details, puzzles and mystery combined. It could be the first children's book of Dan Brown and Robert Langdon (RE: Da Vinci Code)

 MYSTERY BOOK of surprises. 

Secret, secret I got a secret?

NO SECRET. It would be nice to have secrets. 
 

 SECRETS ONLY IN A NOVEL OR IN BOOKS.