* The Torah (Pentateuch): Genesis, Exodus, Leviticus, Numbers, Deuteronomy.
* The Nevi'im (Prophets): Joshua, Judges, Samuel (1 & 2), Kings (1 & 2), Isaiah, Jeremiah, Ezekiel, and the twelve Minor Prophets (Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum, Habakkuk, Zephaniah, Haggai, Zechariah, Malachi).
* The Ketuvim (Writings): Psalms, Proverbs, Job, Song of Solomon, Ruth, Lamentations, Ecclesiastes, Esther, Daniel, Ezra, Nehemiah, and Chronicles (1 & 2).
It's important to note that while these books are *primarily* in Hebrew, some sections might contain Aramaic passages (particularly in Daniel and Ezra). Also, the exact original language of certain books is sometimes debated by scholars. But the list above represents the common understanding of which books were originally composed in Hebrew.