"Adhesion and Friction: Microscopic Concepts" was the theme of the third workshop on interface phenomena organized jointly by the surface science groups at Dalhousie University and the University of Maine. The first two workshops were dedicated to the discussion of elementary processes governing the reaction rates at surfaces and in bulk materials, i. e. adsorption, desorption and diffusion. In this third year a step towards the understanding of complicated (but practical) issues such as adhesion and friction between different materials was undertaken. The presentations and discussions focused on elementary chemical and physical processes at surfaces and interfaces relevant to adhesion, lubrication and friction and gave an account of the application of surface science methods and techniques to relevant model systems. Clearly, at the time of the conference and the publication of the proceedings the understanding of the chemical and physical mechanisms determining the interaction between two solids is still rudimentary, but the issues involved are attracting the attention of more and more scientists and are now regularly represented at scientific meetings. The conference was held at Dalhousie University in Halifax, Nova Scotia, Canada. The facilities provided an ideal setting for the meeting and lively discussions. On behalf of the participants, we would like to express our grat itude to the staff at Dalhousie University for making our stay so pleasant and memorable."

Diffusion in solids and at interfaces is a very active area of research, as the contributions to this volume attest.

This book contains the proceedings of the first Workshop on Interface Phenomena, organized jointly by the surface science groups at Dalhousie University and the University of Maine. It was our intention to concentrate on just three topics related to the kinetics of interface reactions which, in our opinion, were frequently obscured unnecessarily in the literature and whose fundamental nature warranted an extensive discussion to help clarify the issues, very much in the spirit of the Discussions of the Faraday Society. Each session (day) saw two principal speakers expounding the different views; the session chairmen were asked to summarize the ensuing discussions. To understand the complexity of interface reactions, paradigms must be formulated to provide a framework for the interpretation of experimen tal data and for the construction of theoretical models. Phenomenological approaches have been based on a small number of rate equations for the concentrations or mole numbers of the various species involved in a par ticular system with the relevant rate constants either fitted (in the form of the Arrheniusparametrization) to experimental data or calculated on the basis of microscopic models. The former procedure can at best serve as a guide to the latter, and is, in most cases, confined to ruling out certain reaction pathways rather than to ascertaining a unique answer."