Rita Mae Brown wrote a book called Sudden Death in 1983, in which she paraphrased the quote. The earliest know print of the quote appeared in a 1981 Narcotics Anonymous pamphlet. It seems to have been a relatively well know quote, but we still don't know where it first originated. The exact verbiage of the quote doesn't help us date anything, as people will modernize sayings. We all know "buyer beware," but none of us says caveat emptor anymore (well, almost nobody). I'm not sure that you can say for certain that Mark Twain/Samuel Clemens' accent was "deep southern" considering he was born in Missouri and by age 21 he was working for newspapers all around the country. He certainly wrote in dialect, giving his books a more realistic tone for the setting of the story. Unfortunately, there are no known sound recordings of his voice. Similarly, the quote is neither a metaphor, nor is it whimsical. I don't think we can conclude Einstein avoided that phrase for fear of ridicule. It's certainly possible none of these people had anything to do with starting the phrase. It could have come from anywhere really. Sorry, Aquafish, for hijacking your thread. It's 6AM and I can't sleep. Being the inquisitive person I am, I felt I should research more and see if I could find out anything more specific than mere conjecture (since there's nothing better to do at 6AM).