Professor Bruce Harris has left an indelible mark on public law in New Zealand and across the common law world. In particular, his suggestion that there exists a 'third source' of executive action in addition to statutory and prerogative powers has influenced scholarship and judicial decisions in New Zealand, the United Kingdom and elsewhere. In this Festschrift, leading commentators explore key themes from his work. These themes include the nature of executive power; issues concerning the judiciary; and the future of the unwritten constitution. Contributors include leading scholars, jurists and practitioners from both New Zealand and the United Kingdom.As courts and legislatures around the world grapple with the changing demands made of public law, this volume addresses important questions about the powers of the state, the role of judges, and Crown-Indigenous relations. This book engages with these questions through an approach that is both nuanced and pragmatic. This volume is indispensable for students, scholars and practitioners engaged in the study of common law constitutions in New Zealand and beyond.