Introduction: The Natural Philosophy of Leibniz.- The Problem of Indiscernibles in Leibniz’s 1671 Mechanics.- Leibniz and the Foundations of Physics: The Middle Years.- Why Motion is Only a Well-Founded Phenomenon.- Monadic Relations.- Miracles and Laws.- The Status of Scientific Laws in the Leibnizian System.- Leibniz on the Side of the Angels.- Leibniz and Kant on Mathematical and Philosophical Knowledge.- Leibniz’s Theory of Time.- Leibniz and Scientific Realism.