Infectious diseases have been a problem for military personnel throughout history. The consequences in previous conflicts have ranged from frequent illnesses disrupting daily activities and readiness to widespread deaths. Preventive measures, early diagnosis, and treatment greatly limit the exposures and acute illnesses of troops today in comparison with those in armies of the past, but infections and consequent acute illnesses still occur.Thousands of US veterans of the Persian Gulf War have reported an array of unexplained illnesses since the war ended in 1991. Many veterans have believed that the illnesses were associated with their military service in southwest Asia during the war. This volume of Gulf War and Health evaluates the scientific literature on chemical, biologic, and physical agents to which military personnel in the gulf were potentially exposed and possible long-term adverse health outcomes.