Woosley, Stanford AST 97-31569 Dr. Woosley will continue his program of research into the origin and evolution of chemical elements, the evolution of massive stars, and the mechanisms and outcome of supernovae explosions. He will make a number of improvements to his stellar evolution model, including updated opacities and nuclear reaction rates, improved nuclear reaction networks, the incorporation of effects of mass loss and rotation, and a more thorough treatment of convection and mixing. With these improved model results he will explore the sensitivities of the supernovae explosion properties to the pre-supernova model. He also will study the physics of flame propagation and detonation in degenerate white dwarf stars to develop a better understanding of Type Ia supernovae. In all cases, he will determine the detailed nucleosynthesis, with the continued goal of understanding the origin and evolution of the elements. This suite of investigations has direct application to many related areas of research, such as galactic chemical evolution, the distance scale in the universe, gamma-ray astronomy, isotopic anomalies in meteorites, and particle astrophysics. ***