Then there is J.K. Rowling, once a single mother living on welfare in a coldwater flat in Edinburgh, Scotland. She penned a magical story about a wizard named Harry Potter, which turned into a media empire with six books (a seventh, the final installment, is due in July), four movies and countless other items. To date, worldwide book sales have surpassed 325 million copies. Rowling is now the only novelist among the world's wealthiest.