i had an amazing time reading this book. I read it twice

This is a great book for kids who like mystery and math

awesome spy book. If you like this one, listen to Spy School. This is meant for 10+ and I loved it. My mom did too!

BTW If you like this book, you should definitely check out other series by Stuart Gibbs including Spy School, The Last Musketeer, and FunJungle.

This book is full of mystery and suspense but when it all comes together at the end it all makes sense. Charlie is a child supergenius who is the only one smart enough to deduce where Einstein hid an equation that could save the world... or destroy. Charlie and the CIA have to find the equation before a group of terrorists, the Furies do...