In this modern physics text, the emphasis is on fundamentals. Symmetry arguments are used wherever pertinent. Thus, they play important roles in Special Relativity, Quantum Mechanics, Particle Physics, Statistical Mechanics, and General Relativity (the Schwarzschild Field). In Special Relativity, c is introduced as the parameter linking time to space. Only from experiment is it set equal to the speed of light. But this identification may not be exact. Example problems appear at appropriate places in each chapter. At the end of each chapter there is a list of thought questions and a list of problems.