The Philosophy of Leibniz is Bertrand Russell's first strictly philosophical work, and remains one of the most important studies of Leibniz ever published. This work established an approach to studying philosophers of the past that emphasizes the philosophical rather than the historical. In Russell's own words, ``Philosophic truth and falsehood, in short, rather than historical fact, are what primarily demand our attention in this inquiry.''Russell's interpretation emphasized the logical and deductive power of Leibniz's system in opposition to the standard interpretations that had previously led Russell to believe that ``the Monadology was a kind of fantastic fairy tale.'' This paperback edition of The Philosophy of Leibniz includes an introduction by John G. Slater of the University of Toronto.