WordSmith Tools is an integrated suite of programs for looking at how words behave in texts. You will be able to use the tools to find out how words are used in your own texts, or those of others.
The WordList tool lets you see a list of all the words or word-clusters in a text, set out in alphabetical or frequency order. The concordancer, Concord, gives you a chance to see any word or phrase in context, so that you can see what sort of company it keeps. With KeyWords you can find the key words in a text.