This is the second volume in a sub-series of specially commissioned collaborative volumes on key topics at the heart of contemporary philosophy of law that will be appearing regularly within Cambridge Studies in Philosophy and Law. A distinguished international team of legal theorists examine the issue of constitutionalism and pose such foundational questions as: why have a constitution? How do we know what the constitution of a country really is? How should a constitution be interpreted? Why should one generation feel bound by the constitution of an earlier one? The volume will be of particular importance to those in philosophy, law, political science and international relations interested in what kinds of constitutions should be adopted in countries without them, and involved in debates about constitutional interpretation.