This book grows out of, but substantially develops, my previous thinking and writing on ‘the new Commonwealth model of constitutionalism’. Its immediate origins were three invitations I received during the course of 2009. In February, Hilary Charlesworth of the Australian National University invited me to deliver a presentation on how the new Commonwealth model was working in Canada, New Zealand and the United Kingdom at the Protecting Human Rights Conference to be held that October in Sydney in the midst of the national debate on whether Australia should enact a federal human rights act. As it turned out, the conference took place the day before the National Consultation Committee, established by the Labor Government of Kevin Rudd and chaired by the attending Father Frank Brennan, was expected to release its eagerly awaited recommendation and report. In response to the second invitation, issued by Lorraine Weinrib, I presented the resulting paper at the University of Toronto Law Faculty’s Constitutional Round Table in December, where David Dyzenhaus encouraged me to think about writing a book on the topic and submitting a proposal for his new Cambridge Studies in Constitutional Law series, co-edited with Adam Tomkins. I am very grateful to all three.