If I may, I would like to say a word for my silent (list-wise) co-author Tiffany DeRewal. Tiffany was a junior undergrad in my "Subversive Texts" topics class, in which we read PF. As I recall, she formulated the basic outlines of the MPD theory (which I had never considered) before even finishing her first full reading of the novel. She is a movie buff and attributed the notion to her recent viewing of "Fight Club" (which I still haven't seen, alas). Anyway, I thought her theory had a lot of promise, and she eventually turned it into a term paper and then, the following year, a Senior Honors thesis, which I advised. (By this time I had discovered Nabokv-L and Carolyn's similar theory.) After that, we worked together to write what you now have in front of you. Tiffany has moved on to grad school, where, word is, she is reconstructing Melville in equally outrageous fashion. We will hear more from her, I'm sure.
Thanks to Jim Twiggs for the kind words and rich insights.
Matt Roth