Many viruses make us sick, so of course it is a good idea to find out how they work in order to stop them; in addition, however, scientists have found that the simplicity of viruses' method of replication make them excellent models for exploring the basic mechanics of gene expression and regulation. The faculty of a workshop in Mallorca, Spain, May-June 1992, contribute 21 papers on such aspects as cascade regulation of vaccinia virus gene expression, the regulation of HIV structural protein and virion expression, and the mechanism of internal initiation of translation on poliovirus RNA. Reproduced from typescript. Annotation copyright Book News, Inc. Portland, Or.