Codes and Ciphers

Codes and Ciphers is a general-audience survey of cryptography. Alexander D'Agapeyeff, a Russian-born London cartographer with no formal training in the field, wrote it on commission for Oxford University Press as war approached in 1939. It moves through the history of secret writing from classical substitution ciphers to the code and cipher systems then in commercial and military use.

On the book's final page D'Agapeyeff set a 400-digit challenge cryptogram inviting readers to test their skill against it. No one has solved it. D'Agapeyeff later said he could no longer remember how he had encrypted the passage. By his son's account he was embarrassed by the episode, and cryptographers have continued to attempt the cipher into the twenty-first century. Accounts differ on when the puzzle was dropped from the book. The standard secondhand-trade description states it appeared only in the 1939 first edition; a collector who compared physical copies found it still present in the 1949 Compass Books printing and removed only from 1952 onward. This copy is the 1949 Compass Books edition (Compass Books / Geoffrey Cumberlege, Oxford University Press), revised and reset to 149 pages. Its exact printing has not been confirmed against a physical inspection of the copyright page, so whether this specific copy carries the cipher is not established.

D'Agapeyeff had written an earlier manual on cartography for the same press and took on this book as a commercial assignment rather than as a specialist in the subject. Codes and Ciphers went through several editions between 1939 and the 1970s. It is remembered today chiefly for the challenge cipher that its own author forgot how to solve.