As you can see from the picture, George's Secret Key to the Universe is written by Lucy and Stephen Hawking. Lucy Hawking is an accomplished author and journalist. Stephen Hawking is Lucy's father and accomplished theoretical physicist. The two teamed up to write this wonderful book! It's written at an upper grade school level and designed to teach kids about the Universe. Awesome! My daughter's first book by a Hawking!
My daughter dug into it right away at the library and had already read a good chunk of it before we left the library. I encourage you, on your next trip to the library, to check and see if it's in stock. If your kids love science, they'll likely love this book.