Cryptograms are puzzles that have a form of encrypted text embedded within them. These messages are generally referred to as ciphers. The difficultly of solving ciphers can be simplistic or very complex. It all depends on the purpose of the puzzle. Cryptograms were used in the Middle Ages for educational purposes, but they slowly found their use in being able to transmit and receive secret messages.
These cryptogram puzzles can be really fun for students. The best way to approach any cipher is start with any single letters found with the cipher. In the English language, those can be only one of two letters (a or I), since those are the only words that would follow mechanics. Then move on to the letters (E, T, A, O, I, N) which are the most common letters in the language. If you spot any contractions, work off of them. Your last easy step to move on to words composed of two or three letters. These worksheets will give you a great deal of practice more with cryptograms.