J.O. Urmson was Emeritus Professor of Stanford University and an Emeritus Fellow of Corpus Christi College, University of Oxford, UK and his publications include Philosophical Analysis: its development between the two world wars (1963), The Emotive Theory of Ethics (1968); Berkeley (1982), and Aristotle's Ethics (1988).
A. J. Ayer was the Wykeham Professor of Logic at the University of Oxford. His other books include Language, Truth, and Logicand Logical Positivism.Graham Macdonald is professor of philosophy at the University of Canterbury, Christchurch, New Zealand. Among other publications, he is the editor of Perception and Identity: Essays Presented to A. J. Ayer with His Replies.