This book proposes a reflection on Montesquieu's political thought and the tension between the power to punish and individual rights. What does it mean to say that «it is on the goodness of criminal laws that the liberty of the subject principally depends»? Linguistic and conceptual analysis, comparison across legal doctrines and historical contextualization are the analytical tools utilized here to answer this crucial question. From the perspective of the philosophy of law, we rediscover the powerful normative dimension of The Spirit of the Laws.