"These two volumes must be welcomed in particular for the illumination they shed ... on Wittgenstein's already published discussions ... the characteristic deluge of examples, analogies, questions and challanges is as ever, maddening, provoking and thought-provoking, and with the earlier-published works they constitute not just the most detailed but also the best treatment of these profoundly important issues."Kathleen Wilkes, Times Higher Education Supplement