The word derives from the Greek biblia, meaning ‘books’, and the plural witnesses to the fact that the Christian Bible is not a unity but a collection. The Old Testament consists of twenty-four books written in Hebrew (except for a few passages in Aramaic) and is often called the Masoretic text. At the Reformation the Hebrew books were rearranged and some were divided and so became thirty-nine in all, which is the number in the English AV and subsequent revisions. Roman Catholics, however, included as deuterocanonical works additional books from the LXX, so the Catholic OT contains forty-three books.

The Hebrew Bible was traditionally divided into three parts—the Law, the Prophets, and the Writings:

"The Law (Torah): the first five books, the Pentateuch: Genesis, Exodus, Leviticus, Numbers, Deuteronomy." "The Prophets (Nebi'im): Joshua, Judges, Samuel, Kings; the Latter Prophets: Isaiah, Jeremiah, and Ezekiel; and the Twelve Minor Prophets: Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum, Habakkuk, Zephaniah, Haggai, Zechariah, Malachi." "The Writings (Ketubim): Psalms, Job, Proverbs, Ruth, Song of Songs, Ecclesiastes, Lamentations, Esther, Daniel, Ezra–Nehemiah, Chronicles."

Jews use the acronym Tanak for their scriptures: it is a made-up word from the initial letters of Torah, Nebi'im, and Ketubim. The Greek translation of the Hebrew Bible known as the Septuagint (LXX) adds: 1 Esdras, Wisdom of Solomon, Ecclesiasticus (or Sirach), Judith, Tobit, Baruch, the Letter of Jeremiah, 1, 2, 3, 4, Maccabees, and additions to Daniel and to Esther.

It is not entirely clear which books were accepted as authoritative in Palestine in the time of Jesus, but by about 90 CE the rabbis restricted the canon to the Hebrew text, and this narrower list was preferred by several of the Fathers, though generally the Christian Church used and accepted the Greek OT. At the Reformation this larger list continued to have the authority of the Roman Catholic Church as defined at the Council of Trent, but for the most part Protestants preferred the Hebrew OT and regarded the other books as Apocrypha (‘hidden’ or excluded), since they contained doctrines, like prayer for the dead, which were repudiated by Protestants.

The NT consists of twenty-seven books written in Greek, though the process of determining the canon was tortuous: the four gospels of Matthew, Mark, Luke, and John; epistles to the Romans, two to the Corinthians, Galatians, Ephesians, Philippians, Colossians, two to the Thessalonians, two to Timothy, Titus, Philemon, Hebrews; the epistles from James, two from Peter, three from John, Jude; and the Revelation.

Chapters and verses were invented for convenience at quite late dates: the Jewish Masoretes—rabbinical scholars of the period 500–1000 CE dedicated to preserving the correct Hebrew text—divided the books into verses. The NT was divided into chapters by the English Archbishop Stephen Langton (d. 1228) and verses were first introduced in 1551 in the Greek and Latin editions of the NT of Robert Stephanus in Geneva and reproduced in the English Geneva Bible of 1560.