Previous volumes of this Handbook, under the direction of its originators, Doerr and Hallauer, have presented the theoretical and practical aspects of virology as then known in an integrated and masterly fashion. The present editors, C. Hallauer and K. F. Meyer, have tried to adhere to the high traditions of the founders while attempting to meet modern requirements arising from vast expansions in newer knowledge. With the aid of a group of experts they have succeeded admirably. Following previous editions this one presents, in a general section, discussions of important modern technological and methodological advances, followed by a special section comprising discussions of specific viruses or groups of viruses in monographic style. With reviews of historical developments in the various fields and complete evaluations of the present state of knowledge in each, the volume serves very satisfactorily as a handbook for present use and a reference work for the future.