This is the first volume of an intended series of periodically published, single volume, critical reviews indicating the progress of clinical endocrinology. The editor is Director of the Medical Research Institute of Michael Reese Hospital in Chicago. For this purpose, he has gathered for this initial volume 79 articles by an almost equal number of authorseach dealing with a different phase of the subject. The articles are short, readable, and to the point, averaging 7 pages in length. While essentially practical in their approach, the various authors give adequate emphasis to experimental and theoretic background material, and a comprehensive, up-to-date bibliography accompanies each article.