Just as there's little dispute about the darkness of Twain's late writing -
and by "dark" I think we all mean dwelling on the futility of human effort
and the senseless tragedy of human interaction - there can be little dispute
that Sam Clemens fought darkness his entire life. Perhaps a better reading
of the last two decades' work is that he continued his struggle against
darkness, but that he'd become more intimate with his enemy, and sometimes
gave in to it. Maybe the deaths and bankruptcy weakened his resolve, but I
think Clemens at last recognized that one futile human effort is the fight
against darkness. Through it all, he still regarded the struggle as
necessary, and that sense of necessary futility more than anything makes the
late work so moving, so absorbing and so lasting.
Of course, he might only have been in need of a dose of lithium.