The short answer is sixty-six in a Protestant Bible: thirty-nine in the Old Testament and twenty-seven in the New. Catholic Bibles contain seven more in the Old Testament, and Orthodox Bibles contain several more again. The New Testament is the same twenty-seven books in all three.

Why the number differs

The extra books are sometimes called the Apocrypha and sometimes the Deuterocanon. They were written between the Testaments and were included in the Greek translation of the Jewish Scriptures that early Christians used. Protestant reformers set them apart on the grounds that the Hebrew canon did not contain them. Nobody disputes that they exist or that they are old; the disagreement is over whether they carry the same authority.

How the Old Testament is arranged

Not chronologically, but by kind of writing. First the five books of Moses, then the history from entering the land to exile and return, then poetry and wisdom, then the prophets, longer ones first.

This matters practically: Psalms sits in the middle of the Bible not because it happened then, but because that is where the poetry is shelved.

How the New Testament is arranged

Four accounts of the life of Jesus, then one history of the first thirty years of the church, then letters, then Revelation. The letters are ordered roughly by length, not by date, which is why the earliest letter is not first.

What this tells you about reading

A library arranged by type is not meant to be read front to back. Knowing which shelf you are on tells you how to read what is in your hands: history reports what happened, law addresses a particular nation at a particular time, poetry says true things in figures, letters answer questions from specific churches, and prophecy speaks to its own moment before it speaks to any other.

Most confusion about difficult passages comes from reading one kind as though it were another. If you are choosing where to begin, we have a guide to starting, and the daily readings give you a passage a day without any planning.