Excluding non-copyright works such as the Bible (with an estimated 6 billion copies sold) and the Koran, the worlds all-time best-selling book is Guinness World Records (formerly The Guinness Book of Records). Since it was first published in October 1955, global sales in some 37 languages have exceeded 100 million as of October 2003.

Comparatively, Harry Potter books have sold over 100 million copies and Mao Tse-Tung’s Little Red Book boasts sales of around 900 million.