Here are the top 15 all-time best-selling books. If you’re an aspiring author, it looks like books outlining some sort of religious doctrine would be the way to go. But books about wizardry also have huge potential.

1. The Bible (6.7 billion copies)

2. Quotations from Chariman Mao, Mao Tse-Tung (900 million)

3. The Qur’an (800 million)

4. Xinhua Zidian (400 million — a Chinese dictionary, first published in 1953)

5. The Book of Common Prayer, Thomas Cranmar

6. Pilgrim’s Progress, John Bunyan

7. Foxe’s Book of Martyrs, John Foxe

8. The Book of Mormon, Joseph J. Smith, Jr. (123 million)

9. Harry Potter and the Sorcerer’s Stone, J.K. Rowling (107 million — UK title was …and the Philosopher’s Stone)

10. And Then There Were None, Agatha Christie (100 million)

11. The Lord of the Rings, J.R.R. Tolkien (100 million)

12. Harry Potter and the Half-Blood Prince, J.K. Rowling (65 million)

13. The DaVinci Code, Dan Brown (65 million)

14. Harry Potter and the Chamber of Secrets, J.K. Rowling (60 million)

15. The Catcher in the Rye, J.D. Salinger (60 million)

The other three Harry Potter titles are 16, 17 and 18. The list continues at Wikipedia.