The way in which virus disease has crowded out ordinary bacterial infections is well illustrated by the number of monographs on virology, which now appear with increasing frequency. This volume follows the usual procedure of giving first a general discussion about viruses, their biology, their epidemiology, and the technical methods of dealing with them. This is followed by discussions of individual diseases. Although the book runs to 550 pages, the clinical discussions are quite brief, which shows how large the subject has become. This seems to the reviewer to be an excellent book, which is quite adequate for orientation in the domain of viruses.