Last night I attended a reading here in Washington by Richard Slotkin (author of "Regeneration Through Violence," among other things). He has just published "Abe," a novel based on the early life of Lincoln. Among other things, Abe takes a trip down the Mississippi to New Orleans (a historical fact). And deals with racism.
"Abe" shows a lot of influence of Mark Twain, in both content and style. I remarked on this, and Slotkin said that he had originally conceived "Abe" while teaching "Huckleberry Finn."
I'm considering writing a post-modern essay on "The influence of Mark Twain on Abraham Lincoln."