The practice of medicine changes continually, as science guides the physician to the accomplishment of his objective, the cure of the patient. Study of the history of medicine shows that often a remedy of a disease was discovered before the cause of the disease was known. Often the remedy was unnecessarily complicated, but when the cause of the trouble was discovered, the cure became simple and safe. It is with the better under­ standing of the true nature of thyroid disease that this book is concerned. Those who read it will be able to make their treatments of patients with diseases of the thyroid more simple and more safe. Dr. MASAYOSHI AKISADA and Dr. YOSHIHIDE FUJIMOTO have given to thyroidologists a new way of recognizing cancers of the thyroid. Taking advantage of the fact that many cancers of the thyroid contain minute areas of calcification known as psammoma bodies, they have developed a technique of roentgenographic examination of the thyroid that is sensitive enough to show these tiny opacities and to warn the internist and the surgeon that cancer is probably present. There is no question that this sensitive diagnostic test will prove to be of value comparable to that of mammography.