Joanne (J.K.) Rowling

Citizenship: U.K.

Net worth: $1 billion

Once a single mother living on welfare in a cold-water flat in Edinburgh, Scotland, Rowling is now the only billionaire author on our list. The seventh and last installment of her wildly successful Harry Potter series, Harry Potter and the Deathly Hallows, was released July 2007 to throngs of rabid fans, who made it the fastest-selling book of all time. Over 11 million copies were sold in the first 24 hours. Feeding the Potter-mania: The film version of the fifth book, Harry Potter and the Order of the Phoenix, came out the same month. The popularity of her boy wizard has put the author in the spotlight, with a Rowling documentary airing last year. In November, a New York judge ordered publisher RDR Books to halt publication of a Potter dictionary after Rowling brought a lawsuit against the company.