Ruby Redfort

Today I just read the book Ruby Redfort: Look into My eyes by Lauren Child. It is a fantastic book full of puzzle, codes, mysteries, and spies.
Ruby Redfort is a thirteen year-old girl who happens to be a genius. She is recruited by an undercover intelligence agency called Spectrum. Spectrum hires Ruby as a code breaker to break a code involving a plot to steal billions of tons of gold.
What makes this book so good, I feel, is that Lauren Child really makes Ruby come alive. Ruby is such a funny character, and her personality is scripted to become very, very detailed and funny. She has a sarcastic humor, and a passion of T-shirts that often say things like:  A bozo says what, or In deep trouble. 
I highly recommend this book for any readers out there, from ages 8-20.

Rule #1: You can never be completely sure what might happen next.