A remarkable thinker, Gottfried Leibniz made fundamental contributions not only to philosophy, but also to the development of modern mathematics and science. At the center of Leibniz's philosophy stands his metaphysics, an ambitious attempt to discover the nature of reality through the use of unaided reason. This volume provides a systematic and comprehensive account of the full range of Leibniz's thought, exploring the metaphysics in detail and showing its subtle and complex relationship to his views on logic, language, physics, and theology.