Anagramming: Unjumbling Words
Anagramming is the skill of unjumbling a bunch of letters to reveal the words hidden within them. An anagram is a sequence of letters which have been jumbled up to hide the original word. The important thing is that the same letters appear in both the original word or phrase as appear in the anagram. Often they are used to make humourous comments. For example, an anagram for "william shakespeare" is "I am a weakish speller".
Transposition ciphers work by jumbling up the order of the letters in the plaintext. Therefore the skill of anagramming is key to the cryptanalysis of intercepts that have been encrypted using a transposition cipher.
One interesting point to note here is that it is very easy to spot if a transposition cipher has been used. Using the weakness of the Monoalphabetic Substitution Ciphers, we get a clue. In breaking those we used Frequency Analysis, which told us that the most common letter that appeared in the intercept was most likely "e" in plaintext, since this is the most common letter in English. This means that, since a transposition cipher merely rearranges the letters, but does not change them, if the frequency of the letters in the intercept is fairly similar to that of the language the message is written in, then it is highly likely that a transposition cipher has been used.
This does not give us a method to break the intercept though, merely a way of knowing that it was encrypted using some form of transposition cipher.
Anagramming is not as straightforward as frequency analysis was. There is no given rule of thumb to use to start us off. It is much more of a skill that you need to develop, rather than a process you can just apply. Some people are very good at spotting words hidden within words (the character of Robert Langston in The Da Vinci Code by Dan Brown for example).
A good way to practice your anagramming is to play Scrabble, which completely revolves around being able to find words from a jumbled up 7 letters.
The benefit of an intercept which you know to have been encrypted with a transposition cipher is that you know there are words there somewhere (whereas in Scrabble, there might not actually be a 7 letter word available).
Another part to anagramming is to look for patterns, and more importantly lengths. Often there are clues how long the keyword was in the intercept. This could be given away by the use of nulls, which will always be the same distance apart, or from common words split by the same amount. As with frequency analysis, this is only plausible if the intercept is long enough for patterns to start to emerge.