Viruses encapsulates for the lay reader the enormous scientific and medical contributions that have come from the field of virology. Dr. Arnold Levine presents the story of the scientists behind our current understanding of these infective agents and explains how that knowledge has helped us comprehend life at both the molecular and the human level. Many intriguing facets of viral behavior are explored, as Dr. Levine provides a clear account of their natural history, the mechanisms by which they spread and survive, and the toll they exact on their animal, plant, and bacterial hosts. Dr. Levine celebrates the great successes that have come from viral studies--the development of a wide range of vaccines, the eradication of smallpox, and the insights into the origins of cancer. He also examines the challeges we still face, with a series of interconnected chapters on the specific viruses behind some of our most urgent public health problems, including the viruses that cause AIDS, influenza, herpes, and hepatitis. A concluding chapter on the origin and evolution of viruses touches on some of the most provocative issues in molecular biology today. Viral infections continue to be an immediate health concern of imposing proportions. Viruses is written for the general reader eager to know how we study and confront these diseases and where today's research may lead.