Cryptography: Quickly decoding (almost) every substitution cipher in 3 steps.

Mysterious document, waiting to be decoded. You will be able to do it after reading my instructions.

Mysterious postcards, apparently insoluble codes, unknown historical encryption — if you are into this fascinating kind of stuff, you should know Klausis Krypto Kolumne, a blog written by a top cryptologist Klaus Schmeh. A great treasure chest for everybody interested in codes and encryption.