Code and Cipher Guide (ebook)

In CORE Deception, a key part of the plot is a coded method of communication used by someone (I won't say who right now). Think cipher, not computer code. It's briefly explained in the book so you can follow along without being confused. But wouldn't you love to learn how the ciphers worked so you could do it yourself? Same with the codes used in Association and CORE Deception?

Warning: This guide assumes you've read CORE Deception and Association, or at least don't mind a few spoilers.