Cryptology is a science that deals with encryption and decryption methods. One of the oldest sciences, which originated several thousand years ago and continues to actively develop now. The book tells in detail about the history of the origin and evolution of cryptology and special (“closed”) communication in the Soviet Union and modern Russia. Heroes and traitors in these areas. The history of the development and creation of encryptors and other special equipment to protect against wiretapping of various types of communications. How Soviet intelligence hunted for the enemy’s ciphers and codes and what successes it achieved.