Rapid progress in molecular biology, genetic engineering, and basic research in immunology has opened up new possibilities for application to diagnostic procedures and to clinical research. In a short period a new era of diagnosis dawned, covering nearly all fields of microbiology, immunology, and food technology. In consequence of this rapid development, scientists of many disciplines are involved studying infections of humans, animals, and plants or working in technical microbiology. The application of the newest findings of basic research to diagnostic work and to clinical research covers nearly all fields of microbiology and immunology. Moreover, it underlines the close relationship between diagnosis, therapy, and epidemiology. An outstanding example of these connections is given by the recent development of hepatitis B vaccine. The discovery and identification of a non cultivable agent by physicochemical and immunological methods were the heralds of a new era in the prevention of infectious diseases. This book provides an up-to-date, comprehensive review of developments and future aspects in various fields. I am convinced that the authors have succeeded in furnishing a large variety of new ideas and possibilities. K.-O. HABERMEHL Contents Time Realities in the Evaluation of Vaccines for Safety and Efficacy The Evaluation of Vaccines M. R. HILLEMAN . . . . .