There are lots of intriguing titles that treat this development, 2 of which I will mention here: The Culture of Cynicism: American Morality in Decline. By Richard Stivers, (cultural history and criticism) And Seeing through Cynicism: A Reconsideration of the Power of Suspicion. By Dick Keyes (this last one is more of a Christian response to the problems of cynicism in our culture) Personally, I would attribute much of Twain's darkness in his final period to the traumatic grief associated with deaths of his family members, coupled with his own declining health. That said, I see much evidence for his maintaining hope and kindness and joyfulness in those years, some of which I document in my own book on spiritual crises. Harold K. Bush, Jr. Saint Louis University