As in the earlier editions, the new volume has for its purpose the presentation in a simple form of the important aspects of the diagnosis, prognosis, and treatment of heart disease. Despite its modest claim there is much of value and interest for the cardiologist as well as the general practitioner. The need for the new edition is more than justified by the rapid and dramatic advances in the diagnosis and treatment of heart disease. Within recent years the field of cardiology has been broadened by the introduction of new methods of investigation, such as catheterization of the heart, and by studies in unipolar and precordial leads in electrocardiography. The therapeutic possibilities in the treatment, particularly of congenital heart disease, have been enlarged by introduction of a number of surgical interventions. Previously, the mortality rate for bacterial endocarditis was 100%; use of antibiotics now effects cure in 75% of cases.