Canine parvovirus (CPV) is a new pathogen of dogs that has attracted an impressive body of research. It first appeared during the 1970s, and the disease caused by this virus was reported in 1978. However, aspects of the biology of this virus remain unclear, especially the question of its possible origin. This book presents an up-to-date and comprehensive review of the natural history of CPV and its control by prophylactic vaccination. Particular attention is paid to the techniques used to examine how CPV is related to other parvoviruses. A hypothesis on the origin of CPV is complemented by serological evidence of CPV seroconversion in clinically normal dogs some years prior to the virulent pandemic. A concise chapter on human parvoviruses describes the increasing role of B19 in human disease, including that of an opportunistic pathogen in AIDS patients.