Newton's Principia introduced conceptions of space and time that launched one of the most famous and sustained debates in the history of physics, a controversy that involves fundamental concerns in the foundations of physics, metaphysics, and scientific epistemology. This book introduces and clarifies the historical and philosophical development of the clash between Newton's absolute conception of space and Leibniz's relational one. It separates the issues and provides new perspectives on absolute relational accounts of motion and relational-substantival accounts of the ontology of space time. Earman's sustained treatment and imaginative insights raise to a new level the debate on these important issues at the boundary of philosophy and physics. He surveys the history of the controversy from Newton to Einstein develops the mathematics and physics needed to pose the issues in sharp form and provides a persuasive assessment of the philosophical problems involved. Most importantly, Earman revitalizes the connection of the debate to contemporary science. He shows, for example, how concerns raised by Leibniz form the core of ongoing debate on the foundations of general theory of relativity, moving the discussion into a new and vital arena and introducing arguments that will be discussed for years to come. John Earman is Professor of History and Philosophy of Science at the University of Pittsburgh. A Bradford Book