The Advanced Study Institute (ASI) on "Linking the Gaseous and Condensed Phases of Matter: The Behavior of Slow Electrons" was held at Patras, Greece, September 5-18, 1993. The organizers of the Patras ASI felt that the study of the electronic properties of matter in various states of aggregation has advanced to a point where further progress required the interfacing of the phases of matter in order to find out and to understand how the microscopic and macroscopic properties of materials and processes change as we go from low pressure gas to the condensed phase. This approach is of foremost significance both from the point of view of basic research and of applications. Linking the electronic properties of the gaseous and condensed phases of matter is a fascinating new frontier of science embracing scientists not only from physics and chemistry but also from the life sciences and engineering. The Patras ASI brought together some of the world's foremost experts who work in the field of electronic properties of molecular gases, clusters, liquids, and solids. The thirty five lectures given at the meeting as well as the twenty nine poster papers presented and the formal and informal discussions that took place focused largely on the behavior of slow electrons in matter.