Offering an invaluable introduction to Leibniz's philosophy, this volume collects many of his most important texts, beginning with the Discourse on Metaphysics (1686) and ending with the Monadology (1714). Also included in this work are critical reactions to Leibniz's work by his contemporaries (Antoine Arnauld, Pierre Bayle, and Simon Foucher), together with Leibniz's responses. The editors provide new English translations for all of the texts, preceding each with a summary explaining its background, structure, and content.