The Twentieth International Conference on Low Temperature Physics (LT20) is a triennial conference sponsored by the International Union of Pure and Applied Physics (IUPAC). It is to held in Eugene, Oregon, USA, August 4-11, 1993. The objective is to provide a forum for low temperature physicists from all over the world to meet and discuss new and current research. The proceedings will be published in three volumes. The subject matter of the conference covers the following topical areas: *Quantum Fluids and Solids *Low Temperature Properties of Solids *Superconductivity (including High Temperature Superconductors) *Techniques and Applications