Antiviral chemotherapy has come of age, and, after an initial slow pro gress, the development of new antiviral agents has proceeded at a more rapid pace and the perspectives for their clinical use have increased considerably. Now, 25 years after the first antiviral assay (idoxuridine) was introduced in the clinic, it is fitting to commemorate the beginning of the antivirals' era. In its introductory chapter B.E. Juel-Jensen touches on what may be con sidered as five of the most fundamental requirements of an antiviral drug: efficacy, relative non-toxicity, easy solubility, ready availability...