C N Yang, one of the greatest physicists of the 20th Century, was awarded the Nobel Prize in 1957, jointly with T D Lee, for their investigation of the relationship (parity symmetry) between left- and right-handed states, leading to a discovery that astounded the world of physics -- the nonconservation of parity by elementary particles and their reactions. With R L Mills, he created the concept of non-abelian gauge theories, the foundation of the modern description of elementary particles and forces. Professor Yang has worked on a wide range of subjects in physics, but his abiding interests have been symmetry principles, particle physics, and statistical mechanics.In 1999, a symposium was held at the State University of New York at Stony Brook to mark the retirement of C N Yang as Einstein Professor and Director of the Institute for Theoretical Physics, and to celebrate his many achievements. A noteworthy selection of the papers presented at the symposium appears in this invaluable volume in honor of Professor Yang.

A Conservative Revolutionary (F Dyson); Renormalization of Gauge Theories and Master Equation (J Zinn-Justin); High Tc Superconductivity: Symmetries and Reflections (S C Zhang); When Atoms Behave as Waves: Bose-Einstein Condensation and the Atom Laser (W Ketterle); A Theory of Gamma-Ray Bursts (G Brown et al); Direct T-Violation Measurements and T-Odd Effects in Decay Experiments (L Alvarez-Gaume et al.); The Microscopic World Unveiled by Electron Waves (A Tonomura); The Hidden Information in the Standard Model (G 't Hooft); Possibilities for Spin Physics at High Energy (E Courant); The q-t Puzzle Revisited (M Goldhaber); Research and Development Towards X-Ray Free Electron Laser (L H Yu); Remarks on Yang-Mills Theory (T T Wu).