Is Mark Twain living or is he dead?

Three of the Clemens children died before marrying - Lampton, Susan (Susy) and Jean. Clara did marry and had one daughter, Nina, who is dead with no children. There are no living descendants of Mark Twain.

Update: There is now DNA evidence that Mark Twain does have a great granddaughter, child of his granddaughter, Nina Gabrilowitsch. That book has now been published and is on Amazon.