I: Introduction the Study of the History of Ideas; II: The Genesis of the Idea in Greek Philosophy; III: The Chain of Being and Some Internal Conflicts in Medieval Thought; IV: The Principle of Plenitude and the New Cosmography; V: Plenitude and Sufficient Reason in Leibniz and Spinoza; VI: The Chain of Being in Eighteenth-Century Thought, and Man’s Place and Role in Nature; VII: The Principle of Plenitude and Eighteenth-Century Optimism; VIII: The Chain of Being and Some Aspects of Eighteenth-Century Biology; IX: The Temporalizing of the Chain of Being; X: Romanticism and The Principle of Plenitude; XI: The Outcome of The History and Its Moral