I loved reading this book with my kids. It inevitably reminded me of the Phantom Tollbooth - a young girl finds herself on a quest in a land of whimsical encounters based on abstract concepts. Instead of a watchdog or a humbug, her companion on this quest is a chameleon named Xor who changes color to stand out from his surroundings instead of blending in. Along the way they have to decrypt messages, crack passwords, design algorithms, and more! Many of the concepts Laurie and Xor encountered were already familiar to my kids from Code.org assignments in school, and there's an excellent guide at the back of the book that provides more detailed summaries of each concept. It's both a fun story and a gentle introduction to big ideas.