This award funds the research activities of Professor Edward Witten and a group of postdoctoral researchers at the Institute for Advanced Study in Princeton. This project is devoted to the study of elementary particle physics, including its connections to other areas of study ranging from astrophysics and cosmology to condensed-matter physics and geometry. Current and planned work of the researchers supported by this grant covers a very wide range of topics, including the connections between gauge theory (the modern language of the physics governing the elementary particles), string theory (a speculative proposal for unifying the fundamental forces of nature), and geometry. These researchers will also study the possibilities for new models of particle physics that might be relevant at current and future particle-physics experiments; new methods of computing and studying the ways in which elementary particles scatter off each other; new experimental hints of the cosmic dark matter which makes up most of the matter in the universe; and more. Research in these areas thus advances the national interest by promoting the progress of science in one of its most fundamental directions: the discovery and understanding of new physical laws. This project will also have significant broader impacts. The postdoctoral fellows supported by this project will also gain experience working at a high level on these exciting scientific problems, which have all attracted great interest nationall