Neurotropic Viral Infections is a timely compendium of reviews by noted experts in the field of neurotropic viruses, which cause serious neurological disease in humans. It is timely for a number of reasons. First, it is timely because an increasing number of stories of neurotropic virus infections have played out in the world news over the past decade. These include the spread of West Nile virus infection to New York State and across the North American continent; the emergence in Malaysia of two new paramyxoviruses that cause fatal encephalitis; the resurgence of paralytic poliomyelitis in sub-Saharan Africa as the WHO campaign to eradicate poliovirus mopped up the remaining cases; the sudden outbreak of Chikungunya fever, an alphavirus with neurological potential, in the Southwest Indian Ocean and India; the threat of mad cow disease spreading across the border from Canada into the Western United States; the surprising occurrence of progressive multifocal leukoencephalopathy (PML) in several multiple sclerosis patients and a Crohn's disease patient treated with a powerful new immunosuppressive agent, Natalizumab (Tysabri™), a humanized monoclonal antibody against the integrin α4 on lymphocytes; and, finally, from a therapeutic standpoint, the marketing of a new varicella-zoster virus (VZV) vaccine that promises to substantially reduce the risk of painful shingles in the elderly, as well as the first successful treatment of a young girl with rabies encephalitis in Fond du Lac, Wisconsin.