the average Russian has probably read as much or more Mark Twain than the average American

I find that very difficult to believe. It's been said that Mark Twain was the first truly and purely American writer, and he's still probably the most distinguished as such. I really doubt that Russian school children are required to read Tom Sawyer and Huck Finn. Why would the average Russian care about a Missouri boy's trip down the Mississippi with a runaway slave? The book simply drips with American cultural history.

Unless the Soviets skewed Twain into a communist poster-boy, I can't see how they would be more interested in him than Americans.