The main feature of interest in this book is the emphasis laid by the author on the use of the roentgen ray as a means of determining the existence of mitral stenosis and the progress of the lesion. Changes in the size and contour of the heart and its various chambers, as well as in the hilum shadows, give valuable information as to the advance of the cardiac condition. Such examinations during pregnancy may be helpful in deciding for or against an early emptying of the uterus. In other respects the volume contains, briefly stated, the well known facts concerning the diagnosis and clinical manifestations of mitral stenosis with and without evidences of failing heart. These symptoms and signs, by the way, will generally enable the physician to settle the question as to the serious or progressive character of the valvular and muscular lesions without appeal to the roentgen ray.