Gottfried Wilhelm Leibniz (1646-1716) is one of the most important and influential philosophers of the modern period. He offered a wealth of original ideas in metaphysics, epistemology, ethics, and philosophical theology, among them his signature doctrines on substance and monads, pre-established harmony, and optimism. This volume contains introductory chapters on eleven of Leibniz's key philosophical writings, from youthful works ("Confessio philosophi", "De summa rerum"), seminal middle-period writings ("Discourse on Metaphysics", "New System"), to masterpieces of his maturity ("Monadology", "Discourse on the Natural Theology of the Chinese"). It also covers his two main philosophical books (New Essays on Human Understanding and Theodicy), and three of his most important philosophical correspondences with Antoine Arnauld, Burcher De Volder, and Samuel Clarke. Written by internationally-renowned experts on Leibniz, the chapters offer clear, accessible accounts of the ideas and arguments of these key writings, along with valuable information about their composition and context. By focusing on the primary texts, they enable readers to attain a solid understanding of what each text says and why, and give them the confidence to read the texts themselves. Offering a detailed and chronological view of Leibniz's philosophy and its development through some of his most important writings, this volume is an invaluable guide for those encountering Leibniz for the first time.