I realize this is a broad question and if you want to close it I understand entirely but I can't think of a better place to ask.
From my own reading, I believe there are statistical methods which can be applied to give a text a "fingerprint"--frequency of certain words in the text, consistent misspellings of some words and things of that nature, I'd guess. It seems this "fingerprint" can be used to help to identify probable authorship--two texts which have very similar fingerprints are more likely to have been written by the same author. If I wanted to get an introduction to the subject:
1.) What's the proper name for such a field of study? (I ask this so I'll know what I should be searching for at libraries and such.)
2.) Could anyone recommend an introductory (think 1st year college) text on the subject?
As I say, I know this is a broad question but I can't think of a better way to ask it. Feel free to edit mercilessly.
By the way, I don't think I've tagged this question correctly either but since I'm not sure of the proper terminology, I'm unsure how to tag it.