A physician, Richardson was a founder of the Newcastle Research Group whose findings are presented here. Drawing on decades of his own work and the work of his colleagues, Richardson describes numerous case studies that illustrate his theories about viruses and their effects. In particular, he raises questions about the relationship between host and virus; the aftereffects of viral illnesses on the cardiovascular, nervous, endocrine, and other systems; the varied effects of viruses on different members in a family; and the effects of viruses on mother and fetus during pregnancy.