200 years ago, Thomas J. Beale hid a treasure and wrote a cipher that has been unbreakable until today…that is until Calla Cress starts to read it. Now, some

An international team of scientists is sent to an abandoned island to investigate a mysterious technology, only to face a terrifying discovery that defies imagi

This vintage book contains Alexander D’Agapeyeff’s famous 1939 work, Codes and Ciphers - A History of Cryptography. Cryptography is the employment of codes

The lost city of Atlantis of the Sands: real or myth? Calla Cress is a top-notch spy for the International Security and Treaty Force (ISTF), but her latest miss

"As gripping as a good thriller." --The Washington Post Unpack the science of secrecy and discover the methods behind cryptography--the encoding and decoding of