I argue that the current view (as held by, eg., Warnock, Anscombe and Stenius) of Wittgenstein's theory of language in the Tractates is mistaken. This view maintains that Wittgenstein's theory is one of 'isomorphism'; that, roughly, a sentence has meaning in virtue of its being a facsimile of a fact or possible fact. But a detailed study of significant passages in the Tractattis shows that Wittgenstein held no such view. His use of important terms, such as Salz, Bild, Sachverhalt, Tatsache (...) , etc., has been crucially misunderstood. There is no isomorphism. The theory is not about sentences at all, but about talking sense. (shrink)