Christof Heyns was UN Special Rapporteur on extrajudicial, summary or arbitrary executions and member of the UN Human Rights Committee. He passed away in March 2021, working on this book. Frans Viljoen, LLD (Pretoria), is Professor of International Human Rights Law at and Director of the Centre for Human Rights, University of Pretoria. He authored International Human Rights Law in Africa (OUP, 2012). Rachel Murray, PhD (W England), is Professor of International Human Rights Law at and Director of the Human Rights Implementation Centre, University of Bristol. She authored numerous publications on human rights implementation.