Stuart Gibbs: My name is Stuart Gibbs and I am the author of Charlie Thorne and the Last Equation. I was inspired to write this series because when I was a kid there wasn't that much middle-grade being written for me. So I used to read a lot of the books that were written for my parents and there were a lot of books where, it was always like a person who was thrown into the world of espionage and action and adventure without really being prepared for it, just an innocent person who got mixed up in it and they would end up having these adventures all over the world and having all sorts of bad guys and double-crosses, and I actually really enjoyed those books, but I probably didn't fully understand what I was reading because I was a kid trying to read books for adults.

And so I thought that it would be really fun to try and write a book like that targeted for my readers, to write a middle-grade book that was full of action and adventure and globe-trotting all over the world, to all these exotic locations and having all these great action sequences.

I did read a lot of books that had inspired me when I was a kid, and I actually ended up doing a lot of research as well. The book is somewhat based on travels that I'd taken anyhow and places I'd gone, but there were a few times when I thought like, "Oh, this would be a great place to set an action sequence," and I would go there and look it over, and it really is amazing how many more ideas you can get by visiting the place that you want your story to go, than just reading about it. Albert Einstein is at the center of this book. It centers around a discovery that he had made, so I actually ended up doing a tremendous amount of research about Einstein, but then just other geniuses as well.

One of the very important things about this book is that my hero is a young girl. It's my first female heroine, and when you're studying who the great thinkers and scientists are throughout our history, most of them are white men, and as you research genius, you realize it's not because white men have been smarter than everybody else all along, it's because they have been given opportunities that other people haven't, so we've been ignoring the potential contributions of not just the women on our planet, but people of other ethnicities and we've been doing that for thousands of years. It's a real shame, so it became very important to me to make my central protagonist in this a girl because she was going to be going into a world of a lot of men, so I didn't want it just to be a boy in a man's world. I wanted to be a girl in this man's world.

I'm going to read an excerpt that is from a little earlier in the book before Charlie has actually shown up, but it's where one of our heroes, Agent Dante, who is convincing the head of the CIA that they need to bring Charlie aboard to help them track down the last equation.

"'Charlie's mind is wired differently than ours,' Agent Garcia said. 'She knows everything about everything. Science, history, art, you name it.'

"'Perhaps, but there are other characteristics of her personality that are more worrisome.' Director Carter tapped some of the reports where she had made notes. 'Rebellious, headstrong, conceited, disrespectful of authority.'

"'You know who else was like that as a child?' Agent Garcia asked. 'Albert Einstein, as well as Leonardo da Vinci, Isaac Newton, Charles Darwin, Benjamin Franklin, and every other groundbreaking genius you can name. Anyone that brilliant is going to chafe with authority, because they're smarter than the authorities.'

"Dante leaned across the conference table. 'The CIA has been searching for Pandora ever since Einstein died, and we've gotten nowhere. So maybe we need someone as smart as Einstein to find it, and the closest person we have to Einstein right now is her.' Dante thumped his finger on the photo of Charlie Thorne."