Book of Nahum Summary: The Fall of Nineveh and the God of Justice. Nahum is one of the least read books of the Bible, but its message is thunderous: God’s judgment is sure. Written about the fall of Nineveh, the capital of Assyria, Nahum is a prophetic taunt-song celebrating the downfall of one of the most violent empires in history. It is a reminder that God’s justice may seem delayed, but it is never denied.