An encrypted postcard from the 1870s is written in a strange code. Can a reader solve it?

In October 1984 unemployed German food engineer Günther Stoll died of murder or accident. Shortly before his death he had written the word YOG’TZE on a piece of paper. Neither the reason of Stoll’s death nor the meaning of YOG’TZE has ever been found out.

An encrypted message from 1939, sent from the German battleship Schleswig-Holstein to an address in Kiel, Germany, waits to be solved. Can a reader help?

In April 1862 Civil War general Robert E. Lee received an encrypted note from a Joseph E. Johnston. According to the library that owns this document, the encryption is unsolved.

A postcard from 1909 bears an encrypted message and an unusual spelling of a remarkable rock. Can a reader solve these mysteries?

The best-selling novel “The Gold Bug Variations” from 1991 contains an encrypted dedication. It has never been deciphered.

For decades, members of the American Cryptogram Association have tried to decipher an encrypted note found in Denmark – but to no avail.

In 2006 a couple from Erba, Italy, murdered four neighbors. An encrypted letter from this criminal case is still waiting to be solved.

The Zodiac Killer has hit the cinemas again. In a new film titled “Awakening the Zodiac” the code of the killer is broken.

A reader from the Philippines has asked me for help. Can somebody solve the crypto puzzle he is currently working on?