The bilingual edition "Monadology and Other Metaphysical Writings" allows for a precise study of Leibniz's metaphysics from the mid-1680s, when the "Metaphysical Treatise" was created, until the end of his life thirty years later, when Leibniz developed his theory of monads. His three longer treatises on metaphysics were not published by Gottfried Wilhelm Leibniz (1646-1716) himself, but they have significantly shaped the image of the philosopher since the 18th century and have greatly influenced our understanding of modern metaphysics. With the doctrine of the monad as the principle of the uniqueness of being, Leibniz developed an idea that became foundational for the development of modern thought as a whole: the idea of individuality.