This experimental project will advance the fundamental understanding of phase transitions, and critically test theoretical models, using advanced methods of laser light scattering spectroscopy. Specifically, the liquid-glass transition will be studied, with emphasis on the dynamics of supercooled liquids and the physical mechanism underlying the liquid-glass transition. The quantitative comparison of the measurements with theory will focus on, but not be limited to, the Mode Coupling Theory, which provides a detailed set of predictions for the dynamics of supercooled liquids and their evolution with temperature. The critical evaluation of the several theories will include, in addition to the light scattering data, data from collaborating groups using neutron scattering, dielectric susceptibility, and molecular dynamics techniques. %%% This project will advance the fundamental understanding of phase transitions, and critically test theoretical models, using advanced methods of laser light scattering spectroscopy. Specifically, the liquid-glass transition will be studied, with emphasis on the dynamics of supercooled liquids and the physical mechanism underlying the liquid-glass transition. The quantitative comparison of the measurements with theory will focus on, but not be limited to, the Mode Coupling Theory, which provides a detailed set of predictions for the dynamics of supercooled liquids and their evolution with temperature. The critical evaluation of the several theories will include, in addition to the light scattering data, data from collaborating groups using neutron scattering, dielectric susceptibility, and molecular dynamics techniques. ***