During 1939, the New England Journal of Medicine ran a series of articles covering recent progress in the various specialties and in other interesting aspects of medical knowlege. This books consists of a collection of these articles. The fifty-four authors were carefully chosen, and the sound background of each is evident in the presentation of his subject. Each contributes from his knowledge the important developments in the field considered. Such a review is probably far more valuable than an attempt to cite every contribution to the literature, and it certainly provides much more interesting reading. Both the specialist and the general practitioner may find here practical help in diagnosis and treatment, as well as new facts to add to his fundamental knowledge.