This Keynote Lecture was given at the Eleventh International Iris Murdoch Conference at Chichester on the 31st August, 2024. Justin is Professor of Philosophy at Brown, USA. There are philosophers who have said that late 20th century philosophical works do not need commentaries in the way that the writings of Plato and Aristotle, or Kant and Hegel do. Russell and Strawson, or Kripke and Lewis — and others at least in the English-speaking academic world — have committed themselves so much to clarity and a kind of professional *limitation* that they will have followers and opponents, but won’t need expository or explanatory commentary. But Wittgenstein is evidently an exception and so, I think, is Murdoch. What makes philosophical commentary valuable when it is? What kinds of work does it, or should it, do? Which kind of institutional structures promote one kind of writing and which another? And what kind of exception is Murdoch? These are questions, I think, worth exploring.