I also have a few things to say about Calvinism and Twain in my book,
MT AND THE SPIRITUAL CRISIS OF MY AGE.  I really love the letter
exchange in around 1902, between Twain and Joe Twichell, about
Jonathan Edwards's book FREEDOM OF THE WILL.  Very funny stuff.  It
has the additional strength of containing savvy theological critique
from both writers.

ps -- it occurs to me to say that the term Calvinism is probably one
of the more misused and misunderstood terms in our national
vocabulary.  it would rank right up there with things like
"evangelical" "fundamentalism."  Things like that.  Or, in our own
field:  "realism"; "postmodernism".

Caveat Emptor.  I have noticed over the years how it has been twisted
and abused in often brilliant ways by critics and historians who
either have an axe to grind, or wish to dull and already too-sharp
axe.  I certainly tried not to do either that in my own work.

Harold K. Bush, Ph.D
Dept. of English, Saint Louis University