1. A method to determine whether an unidentified author of a textual work corresponds to a known author, the method comprising the steps of: obtaining a known sample of text of the known author; selecting from the known sample a known grammatical unit; parsing and analyzing the known grammatical unit to produce known grammatical unit level data; selecting from the textual work an unknown grammatical unit; parsing and analyzing the unknown grammatical unit to produce unknown grammatical unit level data; and comparing the unknown grammatical unit level data to the known grammatical unit level data.