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.