When my colleagues and I began the task of assembling this volume, several difficult questions arose: For whom were we writing? Was the purpose to eluci date psychiatric or medical presentation? Should references reflect specific to pical areas, or lead the reader to a more general view of a particular topic? Would a symptom or system approach best serve the reader? Should the volume cover a few areas in detail, or attempt to survey a larger area of knowledge? The present text reflects an attempt to answer these questions. It is designed for the student of medicine who desires a broader understanding of those medi cal illnesses that produce psychiatric aberration. We hope it will be of assis tance to the medical student or house officer studying medicine, neurology, family practice, pediatrics, or psychiatry; as well as to the practicing clinician who wishes a refresher on this subject or a reference for his library. The text is intended to strike a useful balance between medicine and psychiatry by provid ing a list of differentials for specific symptoms or conditions, as well as sugges tions for medical evaluation. References have been chosen which we hope will assist the reader in further study. We have attempted to diversify them and list a spectrum of articles that deal with both academic and practical treatment considerations. The initial volume is divided into four sections that address both a symptom and system approach."