In mid July 2013 The Sunday Times in London revealed that Robert Galbraith, who had written a detective novel called The Cuckoo's Calling, was in fact JK Rowling, the author of the Harry Potter books. This story has been widely covered (NY Times story here) but most of them don't say much about how the "stylometric" analysis was carried out. I think that this is an excellent story for those of us who put a little NLP and "computational classification" in our courses so I started looking for some relevant sources.
The best one I found so far was a report by Patrick Juola of Duquesne University, who did the analysis, so I'd trust him as the best source of how it was done. The report is called Rowling and "Galbraith": an authorial analysis , an extremely readable case study that also tells a bit of the history of authorship analysis, including a mention of the classic work by Mosteller and Wallace that determined that James Madison and not Alexander Hamiilton was the author of some of the Federalist Papers (discussed in my lecture notes from Oct 18 of last year).
There is a story today (July 29) in the Chronicle of Higher Education titled The Professor Who Declared, It's JK Rowling that goes beyond Juola's piece, even introducing the concept of "adversarial stylometry" - what you do to diguise the authorship of a text. A tool that stripped out or changed the key words that would identify an author would be useful for whistleblowers or dissidents.
(Sorry 'bout the link, which might smack you into a paywall... it works for me but that's because i have the massive resources of the UC Berkeley library working in the background to make links work).