Gregory Landini is Professor of Philosophy at the University of Iowa, USA. He is the author of four books on the founding figures of analytic philosophy, including the groundbreaking Russell's Hidden Substitutional Theory in 1998 - explaining how the early substitutional logic ofRussells type-free ontology of propositions, which was planned for his never realized secondvolume of The Principles of Mathematics (1903) evolved into the no-propositions simple typeformal grammar of Principia Mathematica (1910). Its sequel, Wittgensteins Apprenticeship withRussell (2007) argues that Wittgensteins Tractarian doctrines were offered in alliance withRussells 1914 program for scientific method in philosophy with an emulation of Principias logicas its essence. Together with his book Russell (2010), all three earned Bertrand Russell SocietyBook Awards. The fourth book, Freges Notations: What they are and how they mean (2012) is inPalgrave Macmillans History of Analytic Philosophy Series. Landini has written many scholarlyarticles on Russell, including Whiteheads (Badly) Emended Principia and Typos of PrincipiaMathematica in History and Philosophy of Logic, Russellian Facts About the Slingshot inAxiomathes, and Zermelo and Russells Paradox: Is There a Universal Set? and Logicism andthe Problem of Infinity: The Number of Numbers in Philosophia Mathematica. He is a directorof the Bertrand Russell Society.
Landon D. C. Elkind is a graduate student in philosophy at the University of Iowa, USA. He is treasurer of the Bertrand Russell Society and of the Society for the Study of the Historyof Analytical Philosophy. His dissertation, In Defense of Logical Atomism, concerns both thenecessary features of the underlying logic of logical atomism and what doctrines are essentialto logical atomism, especially in light of its historical development.