Our vast Universe is filled with an enormous amount of matter and energy, which are the source of large gravitational potentials affecting all physical phenomena. Because this fact about the size and contents of the Universe was not known when our fundamental theories of dynamics and relativity were completed by the 1920s, the current theories - based as they are in empty space - fail to incorporate cosmic gravity. Though the current theories are consistent with the majority of empirical facts, there are some crucial discrepancies, which demand a drastic shift to a cosmic gravitational paradigm for the theories of relativity and dynamics. The book is a detailed and widely accessible account of this paradigm, called Cosmic Relativity, supported by ample empirical evidence. It is established that all motional relativistic effects are cosmic gravitational effects. The new theory of Cosmic Relativity solves and answers all outstanding questions and puzzles about dynamics andrelativity.

C. S. Unnikrishnan is a professor of physics at the Tata Institute of Fundamental Research, Mumbai, India. He was a visiting researcher at the Kastler-Brossel Laboratory of the Ecole Normale Supérieure in Paris and at the University of Paris 13.

His research interests are experimental and theoretical aspects of foundational issues in gravity and quantum physics, including quantum optics. His experimental expertise spans a wide range of studies employing torsion balances, interferometers, laser cooled atoms, and Bose-Einstein Condensates. He was part of the team that pioneered gravitation experiments in India, in a specially constructed underground laboratory. He set up the laser-cooling laboratory at TIFR, Mumbai, in which the first Bose-Einstein condensate in India was produced and studied in an optical trap. His major theoretical contributions are a new paradigm for dynamics and relativity consistent with the gravity of the matter in the Universe (Cosmic Relativity), and the discovery of a universal action mechanics that solves the vexing foundational problems of quantum mechanics, including the quantum measurement problem.

Unnikrishnan is a key member and a proposer-scientist of the LIGO-India project for setting up an advanced gravitational wave detector in India. He is a member of the global LIGO Scientific Collaboration (LSC) for research in gravitational waves, and shared the Breakthrough prize in physics and the Gruber prize in cosmology with the LSC for the detection of gravitational waves.

Unnikrishnan has published over 250 research papers and articles covering several areas of fundamental physics, especially gravitation and quantum physics. This includes also several papers addressing some core foundational and philosophical issues in physics pertaining to locality and causality, unobservables in physics, space-time ontology, and mind-matter problems. His first monograph "Gravity's Time", on the nature of physical time and its relation to cosmic gravity, was published in April 2022.

Unnikrishnan's major interests outside physics research are music and films, especially their structure and process of creation. He has been a columnist, expressing views on science and society, for Malayalam news magazines.

The Paradigm of Cosmic Relativity and Its Evidence.- Space and Time of Our Fundamental Theories.- Electrodynamics, Light and Relativity.- The Special Theory of Relativity and its Empirical Foundations.- Simultaneity and the Synchronization of Time.- The Equivalence Principles.- Einsteins General Theory of Relativity.