Sweeping through the history of Western philosophy of law, Emanuele Castrucci deals with the metaphysical idea of potency as defined by Spinoza and Nietzsche, upsetting entrenched theories of jurisprudence. Castrucci first addresses how the idea of potency can change the meaning of the power ascribed to an omnipotent God. This brings together classical Greek philosophy with Jewish biblical exegesis, which Castrucci links through the juncture of Christianity. He then relates potency to the classical philosophical tradition in Aristotle's Metaphysics and its Arabic interpretations, particularly Ibn Rushd's (Averroes). This leads us to the genesis of natural law theory in Western philosophy, from Augustine to Aquinas and from Duns Scotus to Ockham. Moving on, Castrucci examines the inherently problematic concept of political theology, pitting Spinozan-Nietzschean potency against Kant and Enlightenment natural law to reveal the weaknesses inherent in the Enlightenment system. Finally, Castrucci applies the theories of Carl Schmitt to the philosophical rationalism of the Western tradition, showing us how it has failed to contain absolute power in a juridical sense.