1. A method of selecting and organizing documents from a document corpus in response to a user-provided search expression, the method comprising the steps of: a. locating, within the document corpus, documents matching the search expression; b. identifying, within the located documents, instances of a lexical construct conforming to a selected syntactic pattern; c. assigning dispersion rates to words within the lexical constructs, each dispersion rate corresponding to the number of textually distinct lexical constructs containing the word; and d. ranking the words in accordance with their dispersion rates.