This single volume, with articles contributed by 27 of the foremost virologists of our day, fills a most pressing need. The reader not only is supplied with general information concerning all aspects of the study of viruses and Rickettsia, from immunology to electron microscopy, but also is furnished succinct clinical descriptions of the diseases these organisms produce in human beings. In addition, diagnostic procedures of choice are defined wherever they are available, frequently with full descriptions of the technical steps involved, as, for example, the cold hemagglutinin test. In the reviewer's opinion, the editor has been singularly successful in attaining his stated goal of providing a book to which medical students and practicing physicians may turn for information. Such workers, as well as others with more special interests, will find it well organized, well written, well illustrated and well indexed. The complete bibliographies following each section are particularly attractive.