George and the Unbreakable Code (George's Secret Key #4)

STEPHEN HAWKING was one of history's most brilliant scientific minds. He was a professor at the University of Cambridge for more than thirty years and the recipient of numerous awards and other honors, including the Presidential Medal of Freedom. Professor Hawking wrote many books, including the record-breaking classic A Brief History of Time, and also made documentaries and television series. His life was turned into the Oscar-winning movie The Theory of Everything. Professor Hawking coauthored a series of children's books with his daughter, Lucy Hawking, beginning with George's Secret Key to the Universe. He died in 2018.

LUCY HAWKING is a bestselling children's author and educator. She coauthored the acclaimed seven-book George's Secret Key science adventure series for young readers with her father. Her latest series, Princess Olivia Investigates . . ., shares climate science through character-led adventure storytelling. Lucy's many other science education projects include space-themed books for use in elementary schools, podcasts, and a virtual-reality experience about autism. Lucy lives in London with her family.

XIN LI is an illustrator and picture-book creator. She grew up in China and currently lives in Norway. She studied design and worked for software companies for more than a decade. After having her daughter, Xin realized that her true passion lies in creating art and telling stories.