A 700-page economics tome about income inequality isn't an obvious hit, but it currently tops the list of best-selling books on Amazon. Thomas Piketty's book, "Capital in the Twenty-First Century," was originally written by the 42-year old French economics professor in French, and then translated to English. Amazon (AMZN, Fortune 500) is sold out of the book, which is now in its fourth printing. Publisher Harvard University Press says it's already sold 41,000 copies of "Capital," and is rushing to get another 25,000 print versions to book stores and Amazon as soon as possible. The book is the publisher's first ... (full story)