Andrew M

I had a somewhat embarrassing "one final letter mistake," as I call it. I wasn't sure what "Marked Twain?" meant, but I had filled 39D as ER NURSE, and DEGEARED was in the dictionary, so I just left it at that and went about the rest of the puzzle. Only once the "Something's amiss" message had popped up did I trawl through the grid and find my mistake. Oops!