This book represents a systematic approach to the understanding of electrocardiography in health and disease. It is simply written, and the electrocardiographic changes are described so that the beginner may gain an understanding of them with only a general background of cardiologic training. The outline is much the same as that in similar textbooks. The physiology of impulse conduction and the development of the electrical potential lead up to a consideration of the principles of the recording unit, a résumé of the anatomy and physiology of the specific myocardium and then a discussion of normal and abnormal electrocardiograms. The newer advances in electrocardiography are given. Both nomenclatures for bundle branch block are outlined. Thoracic leads are discussed. The differentiation of the curves in cases of pericarditis and coronary thrombosis is clearly given, and the confusion with pulmonary embolus is pointed out. A discussion of the bundle of Kent is included.