By the age of 75, each one us will have spent ten years in another world - seeing bizarre images, experiencing strange sensations and strong emotions. For everyone, whether they remember them or not, will have spent at least two hours a night dreaming. But do these dreams have any meaning? Bill Oddie agreed to submit himself to the scrutiny of psychoanalysts and the experiments of sleep researchers to find out just how much light science can shed on some of the commonest dream images.