This book is intended primarily for the doctor who is confronted with an electro cardiogram and who wishes to make his own interpretation rather than to rely entirely upon the report of a specialist. The clinical use of the electrocardiogram is the sole concern here and no attempt is made to describe electrophysiology. It is hoped that by beginning with a description of the P wave and its abnormalities the reader will gain confidence and the desire to continue to subsequent sections as he realizes the simplicity of the approach. In a further attempt towards clarity and ease of reading, the text is liberally interspersed with line drawings, all originated by the author, and at the end of each section electro cardiograms are provided, illustrating the abnormalities which have been described. Interest in the electrocardiogram has now spread from the cardiologist to a wide variety of hospital staff, including medical students, house officers, intensive care and coronary care nurses, and anaesthetists. Many general practitioners now record their own electro cardiograms and most have outpatient access to the electrocardiography department of their local hospitals. This book will provide a useful basis for their reading of the electrocardiogram and I hope convince them that its interpretation is well within their capabilities.