As I lay in bed this morning,  I began thinking of which difficult books should be adapted for the silver screen but have not been. Some that were attempted come to mind like The Brothers Karamazov or Breakfast of Champions, that did not work so well critically or at the box office. Others feel Naked Lunch was a great success. I am currently reading William Gass' The Tunnel,  a dark, beautiful book about a Historian writing a book about Nazi Germany. Most of it takes place inside his head and a tunnel he begins digging into his basement. Maybe damn near impossible to film. Chime in. What books do you think should be filmed but have not been?