As the subject of electrochemistry moves into the final quarter of the century, a number of developed areas can be assessed in depth while some new areas provide quantitatively and qualitatively vel data and results. The first chapter, by Kebarle, deals with an example of the latter type of field in which new information of the energetics and equilibria of reactions between ions and solvent molecules is studied in the gas phase and provides interesting basic information for treatments of ions in solution, i.e., ionic solvation. Chapter 2, by Hamann, discusses the behavior of electrolyte solutions under high pressures, a matter of intrinsic interest in relation to ion-solvent interaction and the structural aspects of the properties of ionic solutions, especially in water. This topic is also of current interest with regard to the physical chemistry of the marine environment, especially at great depths. In the article by Bloom and Sok (Chapter 3), models for treatments of molten salt systems are examined quantitatively in relation to the structure of molten ionic liquids and to the statistical mechanical approaches that can be meaningfully made to interpret their properties and electrochemical behavior.