The richest book author is Stephen King, whose estimated worth is over $84 million.
But the top selling author of all time is Agatha Christie.
She wrote 78 mystery novels that have sold an estimated two billion copies.
Agatha Christie also wrote romances under the name Mary Westmacott, and only the Bible has sold more than the four billion copies of novels she has sold.
In 1955, Agatha Christie received the first Grand Master Award from the Mystery Writers of America.