Viruses are responsible for a variety of human, animal, and plant diseases and now represent potential agents of terror. Academic, government, and corporate laboratories have devoted years of effort to the development of strategies to prevent or treat viral infections. Central to the multiplication strategy of all viruses is the process of genome replication. Enzymes critical to this step of the lifecycle have proven to be tractable targets for the development of antiviral agents. Furthermore, genome replication is essential for virus spread and is the main target for the development of antiviral agents. By combining studies of both RNA and DNA viruses - and more - into a single volume, the editors have created a mechanism for cross-talk between the fields that will produce synergy and could lead to more rapid discovery of approaches to treat viral infections.