2020 AAAS/Subaru Prize for Excellence in Science Books: winner in the category of Hands-On Science Book 2021 NCTE Mathical Book Prize Honor Book for Grades 6-8 Codes can carry big secrets! Throughout history, lots of good guys and lots of bad guys have used codes to keep their messages under wraps. This fun and flippable nonfiction features stories of hidden treasures, war-time maneuverings, and contemporary hacking as well as explaining the mechanics behind the codes in accessible and kid friendly forms. Sidebars call out activities that invite the reader to try their own hand at cracking and crafting their own secret messages. This is the launch of an exciting new series that invites readers into a STEM topic through compelling historical anecdotes, scientific backup, and DIY projects.