This book is the result of an international symposium held at the Institute of Virology and Immunobiology of the-University of WUrzburg, Germany, in October 1980. The intent of this symposium was to provide an opportunity to compare the data on coronavirus structure and replica­ tion as well as to discuss mechanisms of pathogenesis. For over a decade coronaviruses have been recognized as an important group of viruses which are responsible for a variety of diseases of clinical importance in animals and man. Recently new and interesting data on the molecular biology and pathogenesis of coronaviruses have become available and this led us to organize this meeting. The uniformity and diversity in this virus group was evaluated from a molecular point of view and the replication of coronaviruses appears to involve aspects which may be unique for this virus group. Additionally, in contrast to other positive strand RNA viruses it became clear that coronaviruses readily establish persistent infections in the host, a phenomenon which may lead to the different subacute or chronic disorders manifested during coronavirus infection. This volume presents a series of articles based upon the scientific presentation given at the symposium. In addition, there are two articles by B. W. J. Mahy and D. A. J. Tyrrell which summarize the current state of art concerning the biochemistry and biology of coronaviruses, respective­ ly. We believe this book will be of interest to all virologists and particularly to both established workers and newcomers to this field. V.