The research will address problems in condensed matter physics which are concerned with explaining and predicting the physical properties of a variety of interesting materials which are currently subjects of experimental studies and technological promise. The properties of these materials are so unusual that new theoretical approaches and techniques are often required. These will be developed based primarily on the methods of quantum statistical mechanics. The materials which will be investigated in this research project include: High-Tc superconductors, the general class of disordered electronic substances, new strongly- correlated metallic and magnetic materials, and quantum solids and liquids.