There are 39 books in the Old Testament of the Protestant Christian Bible.  You might also wish to note that the 39 Old Testament Books are divided into 5 different segments, or groups. These segments are:

The first segment of books in the Old Testament are known as the Books of Law.  In Hebrew, these books are known as the Torah, and in Greek they are known as the Pentateuch. The Books of Law are then followed by 12 Books of History, 5 Books of Poetry and the 17 Books of Prophets.

Books of Law (5):

• Genesis
• Exodus
• Leviticus
• Numbers
• Deuteronomy

The next segment of books are known as the:

Books of History (12):

• Joshua
• Judges
• Ruth
• 1 Samuel
• 2 Samuel
• 1 Kings
• 2 Kings
• 1 Chronicles
• 2 Chronicles
• Ezra
• Nehemiah
• Esther

Books of Poetry (5):

• Job
• Psalms
• Proverbs
• Ecclesiastes
• Song of Songs

Major Prophets (5):

• Isaiah
• Jeremiah
• Lamentations
• Ezekiel
• Daniel

Minor Prophets (12):

• Hosea
• Joel
• Amos
• Obadiah
• Jonah
• Micah
• Nahum
• Habakkuk
• Zephaniah
• Haggai
• Zechariah
• Malachi

The first segment of books in the current English Old Testament are known as the Books of Law.  In Hebrew, these books are known as the Torah, and in Greek they are known as the Pentateuch. Though you will soon discover the Hebrew Old Testament is separated differently, the current English OT Books of Law are then followed by 12 Books of History, 5 Books of Poetry and the 17 Books of Prophets.

Different from the current English version of the Old Testament, the original Hebrew Old Testament was divided into 24 books.  However, it is important to note that the Hebrew Old Testament didn’t have less material than the current English version, rather, the Hebrew OT considered 1 and 2 Samuel, 1 and 2 Kings, and 1 and 2 Chronicles as single books, instead of 2 separate books.  You will also notice Ezra – Nehemiah were also treated as a single writing in the Hebrew text.

Books of Law:

• Genesis
• Exodus
• Leviticus
• Numbers
• Deuteronomy

Books of History:

• Joshua
• Judges
• Ruth
• 1 Samuel
• 2 Samuel
• 1 Kings
• 2 Kings
• 1 Chronicles
• 2 Chronicles
• Ezra
• Nehemiah
• Esther

Books of Poetry:

• Job
• Psalms
• Proverbs
• Ecclesiastes
• Song of Songs

Major Prophets:

• Isaiah
• Jeremiah
• Lamentations
• Ezekiel
• Daniel

Minor Prophets:

• Hosea
• Joel
• Amos
• Obadiah
• Jonah
• Micah
• Nahum
• Habakkuk
• Zephaniah
• Haggai
• Zechariah
• Malachi

The Law (Torah):

• Genesis
• Exodus
• Leviticus
• Numbers
• Deuteronomy

The Prophets:

Former Prophets:

• Joshua
• Judges
• Samuel
• Kings

The Latter Prophets:

• Isaiah
• Jeremiah
• Ezekiel
• The Twelve

The Writings

Poetical Books:

• Psalms
• Proverbs
• Job

Five Scrolls:

• Song of Songs
• Ruth
• Lamentations
• Ecclesiastes
• Esther

Historical Books:

• Daniel
• Ezra-Nehemiah
• Chronicles

The Pentateuch:

• Genesis
• Exodus
• Leviticus
• Numbers
• Deuteronomy

The Historical Books:

• Joshua
• Judges
• Ruth
• 1 Samuel
• 2 Samuel
• 1 Kings
• 2 Kings
• 1 Chronicles
• 2 Chronicles
• 1 Esdras
• Ezra
• Nehemiah
• Tobit
• Judith
• Esther (includes additions to Esther)
• 1 Maccabees
• 2 Maccabees

The Wisdom Books:

• Job
• Psalms
• Proverbs
• Ecclesiastes
• Song of Songs (Song of Solomon)
• Wisdom of Solomon
• Sirach (Ecclesiasticus)

The Prophetic Books:

• Isaiah
• Jeremiah
• Lamentations
• Baruch (includes Letter of Jeremiah)
• Ezekiel
• Daniel (includes Susanna and Bel and the Dragon)
• Hosea
• Joel
• Amos
• Obadiah
• Jonah
• Micah
• Nahum
• Habakkuk
• Zephaniah
• Haggai
• Zechariah
• Malachi

The Pentateuch:

• Genesis
• Exodus
• Leviticus
• Numbers
• Deuteronomy

The Historical Books:

• Joshua
• Judges
• Ruth
• 1 Samuel
• 2 Samuel
• 1 Kings
• 2 Kings
• 1 Chronicles
• 2 Chronicles
• 1 Esdras
• Ezra
• Nehemiah
• Esther (includes additions to Esther)
• Judith
• Tobit
• 1 Maccabees
• 2 Maccabees
• 3 Maccabees

The Wisdom Books:

• Psalms
• Psalm 151
• Prayer of Manasseh
• Job
• Proverbs
• Ecclesiastes
• Song of Songs (Song of Solomon)
• Wisdom of Solomon
• Sirach (Ecclesiasticus)

The Prophetic Books:

• Hosea
• Joel
• Amos
• Obadiah
• Jonah
• Micah
• Nahum
• Habakkuk
• Zephaniah
• Haggai
• Zechariah
• Malachi
• Isaiah
• Jeremiah
• Baruch
• Lamentations
• Letter of Jeremiah
• Ezekiel
• Susanna
• Daniel (includes Susanna and Bel and the Dragon)
• 4 Maccabees (in Appendix)