This book is a valuable, detailed, well written and amply illustrated record of work done with an x-ray machine delivering roentgen rays with energies from 200 to 800 kv. The results in carcinoma of the esophagus, the maxillary sinus, the larynx, the urinary bladder, the breast and the cervix uteri, in malignant tumors of the pharynx and in pituitary adenoma are described.