When I asked a class of fourth and fifth graders what topics they would choose if they could study anything they wanted, cryptography was one of their top choices. Codes & Ciphers is an integrated language arts, math, social studies, and science unit focused on cryptography, the study of secret writing. Students learn about the use of hidden messages from ancient times, how the science has developed, and some of the important people in the field. They experience several types of encryptio