What is Mark Twain last book published?

Mark Twain's last Words, addressed to his sole surviving family member, his daughter Clara, were spoken from the peace of his death bed. "Good-by... If we meet . . ." He looked at her a short time longer, then dropped into sleep, and died in his sleep several hours later.

And today, one hundred years later to the day, he still brings out the best in most people, and the worst in an unhappy few unimaginative asses.