JK Rowling is the world's highest-earning author, making more than £5 every second over the past year, US business magazine Forbes has announced.
The Harry Potter writer, who made a total of $300m (£170m) last year, wrote the first of her best-selling books about the boy wizard in 1997.
Her income was six times more than literature's next-biggest earner, James Patterson, of Along Came A Spider fame.
The magazine described her work as "a children's literary sensation".
A Forbes spokesman said: "It was wizardry that transformed JK Rowling from a destitute single mother on welfare into a best-selling billionaire.
"Over on the big screen, her Potter franchise has already generated $4.5bn (£2.5bn) at the worldwide box office - and she still has three more flicks to come."
Since the first book, Harry Potter and the Philosopher's Stone, was published, the series has taken the world by storm.
The books have sold more than 400 million copies and been translated into 67 languages.
The final instalment of the series, Deathly Hallows, has sold 44 million copies since it came out last summer - including 15 million in the first 24 hours, the magazine said.
Elsewhere on the list was horror author Stephen King in third place, followed by Tom Clancy, best known for his 1984 novel The Hunt for Red October.
At number five was Danielle Steel, with John Grisham and Dean Koontz equal in sixth place.
Best-selling author of Pillars of the Earth, Ken Follett, was in eighth place, while Janet Evanovich, the writer behind the Stephanie Plum novels, was at number nine.
US writer Nicholas Sparks rounded off the top 10.