Adam Gidwitz came to our school one day to talk to us about his books! He wrote grim fairytales and other fictional books. He didn’t talk all about books though, he had a sense of humor and talk to us about how he was in quick sand!  He also talked about a spy book he wrote. I’m pretty sure it was about a kid during the the nazis and he was on a train leaving his home and he heard these voices from little people on his shoulder that only he could see. It was partly based on his family friend who lived in Germany and was in the time of world war 2. The book is called Max in the House of Spies.

https://www.inspireuplift.com/Max-In-The-House-Of-Spies-A-Tale-Of/iu/16879115