Abstract: Explores the contributions of Gottfried Wilhelm Leibniz (1646–1716) to three areas of metaphysics. Part One (Chs. 1–3) is concerned with his determinism, chronicling his efforts to retain a place in his system for contingency, and arguing that his famous denial of alternative possibilities (or transworld identity) for individuals is not dictated solely by his logic, but is largely motivated by metaphysical considerations. Part Two (Chs. 4 –8) studies Leibniz's attempts to provide theistic answers to fundamental questions in ontology, and argues that these substantively metaphysical considerations are more promising as a basis for theistic argument than his proposals for more purely formal development of the ontological argument for theism. Part Three (Chs. 9–13) defends a broadly idealist interpretation of Leibniz's conception of bodies or physical objects, and their relation to simple substances or monads, and tries to show the plausibility and interest of some of its leading ideas.

Keywords: contingency, determinism, history of philosophy, idealism, Leibniz, metaphysics, monads, ontological argument, possible worlds, simple substances, theism, transworld identity