Iason has compiled a book that will be found useful to the specialist in thyroid physiology or pathology, for it apparently provides all the basic information about the development of our knowledge of the thyroid gland from the Egyptians to our day. The book is well illustrated, the paper is excellent and the format such that it can be read with comfort. The author has put his material together in a most orderly fashion, but in so doing the book, from the point of view of the nonspecialist reader, loses background. Focusing wholly on the thyroid, one has the impression that other actors too must have been concerned in the play. But to trace them would have made a much bulkier book and might have diverted the reader from the subject of the dissertation. As it is, the volume is a worth while contribution to our knowledge.