Book excerpt: Pandemics are large-scale epidemics that spread throughout the world. Virologists predict that the next pandemic could occur in the coming years, probably from some form of influenza, with potentially devastating consequences. Vaccinations, if available, and behavioral methods are vital for stemming the spread of infection. However, remarkably little attention has been devoted to the psychological factors that influence the spread of pandemic infection and the associated emotional distress and social disruption. Psychological factors are important for many reasons. They play a role in nonadherence to vaccination and hygiene programs, and play an important role in how people cope with the threat of infection and associated losses. Psychological factors are important for understanding and managing societal problems associated with pandemics, such as the spreading of excessive fear, stigmatization, and xenophobia that occur when people are threatened with infection. This book offers the first comprehensive analysis of the psychology of pandemics. It describes the psychological reactions to pandemics, including maladaptive behaviors, emotions, and defensive reactions, and reviews the psychological vulnerability factors that contribute to the spreading of disease and distress. It also considers empirically supported methods for addressing these problems, and outlines the implications for public health planning.