Dr Dafydd Mills Daniel is Lecturer in Divinity, University of St Andrews. Previously McDonald Lecturer, University of Oxford, he is author of Conscience and the Age of Reason and, with David Mills Daniel, of Briefly: 25 Great Philosophers from Plato to Sartre, Briefly: Nietzsche's Beyond Good and Evil and AS/A2 Ethics and Moral Philosophy. His BBC radio documentaries include: Where do human rights come from? and Sir Isaac Newton and the Philosophers' Stone.

Dr David Mills Daniel is creator of the Briefly series of books on leading figures in the history of western philosophy, from Plato and Aristotle to Bertrand Russell and A.J. Ayer. A former headmaster, researcher at the University of Leeds and A level Chief Examiner, his books include: Briefly: Aquinas' Summa Theologica, Briefly: Descartes' Meditations on First Philosophy, Briefly: Hume's Dialogues Concerning Natural Religion, Briefly: Kant's Critique of Practical Reason, Briefly: Kierkegaard's Fear and Trembling.