Interferons (IFNs) play pivotal roles in shaping the immune responses in mammals and are particularly important for the control of viral infections, cell growth, and immune regulation. These proteins rapidly induce an "anti-viral state" in cells that surround infected cells. In order to survive, viruses have evolved with multiple strategies to evade the anti-viral effects of IFNs. Elucidating the molecular and cellular biology of the virus-interferon interaction is key to understanding issues, such as viral pathogenesis, latency, and the development of novel antivirals. In this book, international experts review current research topics, producing a timely overview of this exciting field. The book opens with a chapter that comprehensively reviews the antiviral effects of extracellular double-stranded RNA - the "viral toxin." This is followed by chapters that review the properties of type I and type III interferons, and the role of interferon-stimulated genes. Additional chapters are devoted to understanding the diverse strategies used by clinically-relevant human viruses to subvert host interferon responses. The book closes with an interesting overview of the clinical application of interferons as antiviral and anticancer agents. It will be essential reading for every scientist involved in interferon or antiviral research and will be a recommended text for all virology laboratories.