As Chairmen of the Electrochemistry and Molten Salts Discussion Groups of the Chemical Society, it gave us great pleasure to welcome the confer ence Highly Concentrated Aqueous Solutions and Molten Salts, which our Groups cosponsored, at St. John's College, Oxford in July 1978. During the meeting the editors of the present volume, and those giving lectures, came to the conclusion that the verbal presentations deserved to be expanded and to be more widely disseminated in a permanent form. Thus the articles which appear in this volume were commissioned and prepared. A greater exchange of information between aqueous chemists and those concerned with molten salts is to be welcomed and to this end the present volume aims to focus attention on the borderline areas between the two in an attempt to facilitate a wider awareness of the concepts and methods appropriate to the respective specialities. Similarly, and parti cularly in the electrochemical field, a greater exchange of information be tween the academic and industrial practitioners of the subject is desirable. T!1e problems involved are not trivial but when the interactions in these largely (but not wholly) ionic liquids are better understood, this wiii surely be to the benefit of all concerned with solution chemistry. Douglas Inman, Imperial College Chairman, Electrochemistry Group David Kerridge, University of Southampton Chairman, Molten Salts Discussion Group v Preface A number of recent events led to the appearance of this text at this particu lar time.