Each letter in a cryptogram stands for another letter; e.g., A=M, B=Z, etc.
Here’s a sample sentence:
CMIXYM HXLP JEQAAMOPTQU, PXOJ XH STOOQXY!
and its solution:
BEGONE FOUL DWIMMERLAIK, LORD OF CARRION!
A few decoding tips:
Consider letter frequency. The most common letters in the English language are: E, T, A, O, I, N, S, H, R, D, L, U.
Consider letter position. E, for instance, is more likely to appear at a word's end than at its beginning.
Punctuation may provide clues. A single letter after an apostrophe is usually S or T. A
comma is often followed by a conjunction; if a 3-letter word,
try AND, BUT, or FOR.
A letter standing alone is almost always either A or I.
Look for repeated letter combinations that might represent common words; words like THE
& AND are bound to show up often.
Double letters at the end of a word will often be LL or SS.
Double letters in the middle of a 4-letter word will often be EE or OO.
The most common 4-letter word with letter pattern ABCA is THAT.
Don't hesitate to use some trial-and-error guesswork, bu don't hesitate to abandon
your initial guesses if they're not working out.
Note: The words that are legible in the coded sentences don't necessarily have
anything to do with the original quotes.