This volume covers a common infectious disease that afflicts millions every year—the flu—but one that has the potential of being at the center of a new pandemic, similar to the one that killed millions during 1918. Influenza examines all aspects of this disease, including: • The influenza virus and how it leads to infection in humans. • The definition of epidemics and pandemics, and a description of the Influenza Pandemic of 1918. • The clinical signs and symptoms of influenza, and how it impacts special populations, such as the elderly and HIV-infected patients • The treatment and prevention of the flu The volume includes a glossary of important terms and a bibliography of accessible works that discuss the disease.