David Greene is an experimental psychologist who first became interested in the study of pets when he noticed their beneficial effect on the youngsters with whom he was working. In particular, children who owned cats seemed less prone to emotional and social difficulties than many of their schoolmates. The author has since devoted an extensive effort of research into gaining a better understanding of the ways in which cats are of benefit to humans. In addition to his psychological research, David Greene carries out a general behavioural consultancy practice for both families and industry.