Bertrand Russell and the Nature of Propositions offers the first book-length defence of the Multiple Relation Theory of Judgement (MRTJ). Although the theory was much maligned by Wittgenstein and ultimately rejected by Russell himself, Lebens shows that it provides a rich and insightful way to understand the nature of propositional content.

In Part I, Lebens charts the trajectory of Russell's thought before he adopted the MRTJ. Part II reviews the historical story of the theory: What led Russell to deny the existence of propositions altogether? Why did the theory...