And how 'bout those early influential furriners like Calvin and Hobbes (I mean the originals), and Locke and Rousseau?

Their books *really* helped shape America. Shakespeare and Milton too. And, face it, Marx & Engels. I guess the Bible and the Talmud go without saying. (It may be premature to add the Quran and the Sayings of Confucius.) All are reasons why America is so diverse.
   
The title of the list should include the word "help." Books don't do everything.

Just thought of another one of vast influence: Alex Comfort's "The Joy of Sex." Of course, he was a furriner too, so he couldn't possibly have written a book that helped shape America, right?