One might also make such a judgment with regard to Susy. Or even Langdon. Large families and untimely deaths were the norm in the 19th century. But to the point of your question, I do believe a case can be made for Livy's beneficial impact as editor in residence on Sam's literary work. The tired saw about Livy lessening the vitality of Sam's writing just doesn't wash. But by the time of Livy's death, Sam Clemens was not the same man--his bitterness came to dominate his thinking and his life. Resa Williams has done a good treatment of Livy & Sam, called "Mark and Livy--The love story of Mark Twain and the woman who (almost) tamed him." David H Fears