Gottfried Wilhelm Leibniz (1646–1716) was hailed by Bertrand Russell as ‘one of the supreme intellects of all time’. A towering figure in seventeenth-century philosophy, he was the author of a complex system of thought that has been championed and satirized in equal measure, most famously in Voltaire’s Candide. In this outstanding introduction to his philosophy, Nicholas Jolley examines and assesses the whole of Leibniz’s philosophy. Beginning with an account of Leibniz’s life and work, he carefully explains the core elements of Leibniz’s metaphysics: his theories of substance, identity and individuation; his doctrine of monads; and his important debate over the nature of space and time with Newton’s champion, Samuel Clarke. He then introduces Leibniz’s theories of mind, knowledge, and innate ideas, showing how Leibniz anticipated the distinction between conscious and unconscious states, before examining his doctrine of free will and his solution to the problem of evil. An important feature of the book is its survey of Leibniz’s moral and political philosophy, an overlooked aspect of his work. The final chapter assesses Leibniz’s legacy and the impact of his philosophy on philosophy as a whole, particularly on the work of Immanuel Kant. Throughout, Jolley places Leibniz in relation to some of the other great philosophers, such as Descartes, Spinoza, and Locke, and discusses Leibniz’s key works, such as the Monadology and Discourse on Metaphysics. This second edition has been revised throughout and includes a new chapter on Leibniz and philosophy of language.