It is difficult to chart Iris Murdoch's progress, if only because she has a gift for making the variety of possible plots and characters seem inexhaustible. The result of such plenty is that no new novel of hers is going to retain its air of finality for long: it joins the oeuvre, it confirms the appetite (in author and readers alike) for yet more novels. She herself would perhaps think this response appropriate, given her stress on art's capacity to strengthen our moral curiosity ('Virtue', she once wrote, 'is concerned with really apprehending that other people exist') but it has its problematic aspect, since it produces a nice confusion between quality and quantity. More does seem to mean better for her; imagination and curiosity are near akin, and curiosity can only be fed with particulars fresh-invented each time. Three years and three novels ago in The Black Prince...