In this article, I pay special expository attention to two pieces of philosophically relevant Wittgenstein–Russell correspondence from the period leading up to the ultimate demise of Russell's Theory of Knowledge manuscript (in June 1913). This is done in the hopes of shedding light on Wittgenstein's notoriously obscure criticisms of Russell's multiple relation theory of judgement. I argue that these two pieces of correspondence (the first, a letter from Wittgenstein to Russell dated January 1913, and the second, a letter from Russell (...) to Ottoline Morrell, reporting a tense confrontation with Wittgenstein on 26 May 1913) each refer to what is more or less the same approach to problems concerning the unity and well-formedness of propositions or judgements. However, the view advanced in Wittgenstein's January letter to Russell nevertheless differs in a key respect from the view of Russell's referred to in the May letter to Morrell. The difference involves Wittgenstein's incorporating qualities and relations as unsaturated parts of the copulae of atomic complexes, where these copulae are in turn conceived as logical forms. Because such an approach to logical form (and more specifically, to relations) was philosophically unpalatable to Russell, he undertook an alternative theoretical correction in the context of his 1913 Theory of Knowledge manuscript. This theoretical correction was discussed with Wittgenstein during the tense confrontation on 26 May, and involved deploying a supplemental significance constraint on judgements. It was this significance constraint on judgements, moreover, which was the ‘premiss’ alluded to by Wittgenstein in the context of a June 1913 letter to Russell, wherein he claims to express his objection to Russell's theory ‘exactly.’. (shrink)