Andrew Marr talks to John Gray about our delusional quest for immortality, from Victorian séances to embalming Lenin's corpse to uploading our minds in cyberspace. Equally ambitious has been the quest to create the ultimate living, thinking robot, and the anthropologist Kathleen Richardson assesses how far machines could take over the earth. The science fiction writer Paul McAuley imagines a utopian world in the hostile environs of Jupiter and Saturn, based on a system of favours and patronage. And Dai Smith offers up an alternative history of his native South Wales, which brings together the events, people and writings that have shaped its unique culture.

Producer: Katy Hickman.