Using the theory of evolution, the first modern humans originated in Africa, and from there they migrated to Eurasia and Australasia. These humans carried with them the genetic basis of schizophrenia, the only major illness found to the same extent in all racial groups. This universal distribution shows that the disease must have been present before the races separated. Modern evidence shows that families where schizophrenia is present are also exceptionally creative in many different fields. In this book David Horrobin draws on his knowledge of medicine, of evolution, of psychiatry, of Africa and of nutrition to present the hypothesis that we are human because some of us are schizophrenic and because a "touch of schizophrenia" is associated with exceptional skills of many sorts with a creativity that defines humans and separates us from our nearest primate.