This collection of essays showcases the most important and influential philosophical works of the ancient and medieval period, roughly from 600 BC to AD 1600. Each chapter takes a particular work of philosophy and discusses its proponent, its content and central arguments. These are: Plato's Republic ; Aristotle' Nichomachean Ethics ; Lucretius' On the Nature of the Universe ; Sextus Emperiicus' Outlines of Pyrrhonism ; Plotinus' The Enneads ; Augustine's City of God ; Anselm's Proslogion ; Aquinas' Summa Theologia ; Duns Scotus' Ordinatio ; William of Ockham's Summa Logicae .