Lecture, three hours. Symmetry characterization of phases of matter, phase transitions, Landay theory, order parameters. Applications: superfluidity, liquid crystals, superconductivity, Higgs mechanism. Scaling theory of critical phenomena, correlation functions, critical exponents, renormalization group methods. Goldstone models and topological defects, spin waves, sound waves, Kosterlitz/Thouless transition. S/U or letter grading.