Cameron,

I have studied _The Mysterious Stranger_ as a text representative of the
later mood.  It is useful alongside DeVoto's _Letters From the Earth_, a
collection of later fragmentary writings in the same cynical voice with
regard to Twain's attitudes towards humanity and human history.  The
autobiography is also a useful tool, though it's complicated in terms of
editorial manipulation in a way comparable to that of _The Mysterious
Stranger_.  Neider's is the most accessible of the published
autobiography's, though the liberties he's taken with the author's
intentions are greater than Paine's and DeVoto's earlier attempts at
publishing the autobiography.  All three are in publication, and readily
accessible.  I would argue that Tuckey's _mark Twain and Little Satan_
(1963), and DeVoto's chapter "Symbols of Despair" from _Mark Twain at Work_
(1940)are required reading for anyone who would teach _The Mysterious
Stranger_.

I am currently engaged in research into both _The Mysterious Stranger_ and
the autobiography; I'd be happy to enter into dialogue with yourself or
anyone else with a questions or possible contributions.  I think that
there's room for interpretation outside of the typical focus on the cynicism
and nihilism inherent in the later writings and life-writing.

Best,

JED LaCoste
Dalhousie University