I can add another name to this list: Charles Neider wrote several novels,
the best known of which is probably THE AUTHENTIC DEATH OF HENDRY JONES
(yes, "Hendry," not "Henry"). It is a western novel that was made into the
Marlon Brando film ONE-EYED JACKS. In addition to his many Mark Twain books,
Neider also wrote extensively about Antarctica. Another of his novels,
OVERFLIGHT, is about a man who is the sole survivor of an airline crash into
Mt. Erebus. When he later returns to the mountain to scatter ashes of the
crash victims, the helicopter carrying him crashes, beginning an epic
struggle for survival.