List of Forbes authors,JKR is top.

It was wizardry that transformed J.K. Rowling from a destitute single mother on welfare into a bestselling billionaire. Her adventures of teenage magician Harry Potter and his classmates at Hogwarts became a children’s literary sensation in 1998, when Harry Potter and the Sorcerer’s Stone became a publishing hit. It and the six subsequent books have now sold upwards of 375 million copies worldwide. The final one, Harry Potter and the Deathly Hallows, has sold some 44 million since it came out last summer—including 15 million in the first 24 hours.

1. J. K. Rowling
2. James Patterson
3. Stephen King
4. Tom Clancy
5. Danielle Steel
6. (Tie) John Grisham
6. (Tie) Dean Koontz
8. Ken Follett
9. Janet Evanovich
10. Nicholas Sparks