This essay highlights three aspects of the extraordinarily current relevance of Cesare Beccaria’s On Crimes and Punishments in the 250th year since its publication. The first aspect concerns criminal law, which Beccaria founded anew as a system of individual safeguards against the arbitrariness and excess of punishment – a normative model still largely to be realized today. The second aspect consists in the constituent character of Beccaria’s thought. Together with other Enlightenment thinkers, he paved the way for the political doctrine of limited public powers – the doctrine that would usher in, well beyond the boundaries of criminal law, the contemporary and still largely unaccomplished constitutionalism of legal safeguards and fundamental human rights. The third aspect of Beccaria’s relevance consists in the critical and propositional role he assigned to philosophical reflection vis-à-vis positive law, on the ground of its axiological foundations and a militant defence of the values inherent in the legal artifice.