Newton’s ideas about how to represent space and time, his laws of dynamics, and his theory of gravitation established the conceptual foundation from which modern physics developed. This book offers a modern view of Newtonian theory, emphasizing those aspects needed for understanding quantum and relativistic contemporary physics. In 1905, Albert Einstein proposed a novel representation of space and time, special relativity. The text also presents relativistic dynamics in inertial and accelerated frames, as well as a detailed overview of Maxwell’s theory of electromagnetism, thus providing the background necessary for studying particle and accelerator physics, astrophysics, and Einstein’s theory of general relativity. In 1915, Einstein proposed a new theory of gravitation, general relativity. Finally, the text develops the geometrical framework in which Einstein’s equations are formulated and presents several key applications: black holes, gravitational radiation, and cosmology.