The central subject of this volume is the atomic and molecular physics of heavy par­ ticles as investigated with charged particle accelerators. The natural division be­ tween atomic structure and ion-atom collision studies, and the similar division be­ tween the theoretical and experimental branches of these subjects, are reflected in a parallel subdivision into corresponding chapters. In addition, one chapter is de­ voted to the important interface between atomic and molecular physics with condensed matter physics. A principal aim of the present volume is to provide a compact de­ scription of a number of current interests and trends within the heavy particle structure and collisions field in a sufficiently general, non-specialized way that interested scientists who wish to become acquainted with such interests and trends can do so without becoming bogged down in excessive archival detail. It is, therefore, hoped that the book will be of some use to advanced students who seek a general in­ troduction to these subjects. Numerous, more specialized, archival review articles are frequently referred to in each chapter for the benefit of those who seek more detailed knowledge about particular topics discussed. The editor wishes to acknowledge the support of two U. S. government agencies: the Office of Naval Research and the National Science Foundation, during the preparation of this volume. Sincere thanks are due Mrs. Betty Thoe for her excellent editorial work on the various manuscripts and Mrs.