At this writing the decade of the 1980s is rapidly coming to a close, and it is an appropriate time to review the picornavirus field. During the past decade there has been a remarkable reemergence of interest in picornaviruses and a virtual explo- sion of experimentation. The renaissance of picorna viruses can be attributed to several developments near the beginning of the 1980s. In 1981 the nucleotide sequence of the first picornavirus genome, that of poliovirus, was determined, providing a genetic map that would be the basis for a number of experimental questions regarding gene function and expression (Kitamura et ai. , Nature 291: 547; Racaniello and Baltimore, Proc Natl Acad Sci USA 78: 4887). In the same year it was reported that a cloned eDNA copy of the poliovirus genome is infectious when transfected into cultured mammalian cells (Racaniello and Baltimore, Science 214: 916, 1981). This discovery, which enables construction of poliovirus mutants and recombinants, has since been used for the study of many picornaviruses. Furthermore, the availability of cloned copies of viral genomes permits manipulation of gene products apart from infected cells. Third, the use of hybridoma technology to generate anti- picornavirus neutralizing monoclonal antibodies permitted mapping of antigenic sites (for example, Evans et ai. , Nature 304: 459, 1983). Finally, at mid-decade the three-dimensional structures of poliovirus (Hogle et ai. , Science 229: 1358, 1985) and rhinovirus (Rossmann et ai. , Nature 317: 145, 1985) were solved.