The Charlie Thorne series--which #1 New York Times bestselling author Chris Grabenstein called "a real page-burner"--is now available with all four books in a paperback boxed set! Charlie Thorne is a genius. Charlie Thorne is a thief. Charlie Thorne isn't old enough to drive. And now it's up to her to save the world. Charlie Thorne is not your average twelve-year-old. Brilliant, adventurous, and defiant, she has been forced to help track down and protect the greatest hidden secrets of mankind: an incredibly dangerous equation devised by Einstein, an astonishing discovery by Darwin, the mysterious source of Cleopatra's power, and Newton's secret treasure. To find each one, Charlie must travel the world, facing danger at every turn, cracking codes, solving mysteries, and struggling to stay ahead of the formidable lineup of enemies and government agents who are hot on her tail. This code-cracking paperback boxed set includes: Charlie Thorne and the Last Equation Charlie Thorne and the Lost City Charlie Thorne and the Curse of Cleopatra Charlie Thorne and the Royal Society.