The Bridges of Madison County 50 million

Better known by many for its film version, this 1992 novel is one of the 20th centurys bestsellers despite being on the market for less than a decade. Written by Robert James Waller, The Bridges of Madison County depicts the affair between a lonely, married woman in Iowa and a photographer who visits Madison County to take photographs of the areas covered bridges. At over 50 million copies already sold, this book is one of the most rapidly selling books of all time and was even adapted into a musical in 2013.