Of Ludwig Josef Johann Wittgenstein's philosophical writings available in print, by far the greater part was published after the 1967 Encyclopedia of Philosophy. The year 1967 also saw the publication on microfilm of Wittgenstein's Nachlass. In addition to the Nachlass itself and the posthumously published material from it, there has become available since 1967 a considerable body of Wittgenstein's letters, records of conversations with him, and notes taken by students at his lectures. Altogether, vastly more material is available to the student of Wittgenstein than there was in the mid-1960s. The Tractatus and the Philosophical Investigations remain, however, the central works for anyone trying to understand Wittgenstein's philosophy. The other writings do give a far fuller understanding of how Wittgenstein's later thought developed; they make clear important continuities between earlier and later work that had been difficult to see earlier. The recognition...