Forty years after his death, Hans Kelsen (1881-1973) remains one of the most discussed and influential legal philosophers of our time. This collection of new essays takes Kelsen's Pure Theory of Law as a stimulus, aiming to move forward the debate on several central issues in contemporary jurisprudence. The essays in Part I address legal validity, the normativity of law, and Kelsen's famous but puzzling idea of a legal system's 'basic norm.' Part II engages with the difficult issues raised by the social realities of law and the actual practices of legal officials. Part III focuses on...