The Bible, which ranks as the world's most-read book, has sold 3.9 billion copies. However, many more copies have been given away for free, meaning the actual number of bibles in circulation is unknown. Additionally, since the Bible is sold worldwide, calculating exact numbers becomes tricky.
The first copies of the Bible, known as the Guttenberg Bible, were written and decorated by hand in Latin in 1455. Since then, the Bible has been translated into close to 500 languages and is constantly being translated into additional languages. The most popular version of the Bible in the United States is the King James Version.