With her finger as always on the pulse of our deepest concerns, in "A Number", Caryl Churchill turns her extraordinary dramatic gifts to the subject of human cloning - how might a son feel to discover that he is only one of a number of identical copies. And how would the father feel confronted by these reproachful clones ...? First staged in 2002 to huge acclaim at the Royal Court Theatre, London, with Michael Gambon as the father and Daniel Craig as the sons, "A Number" is revived at Sheffield in October 2006 with real-life father and son, Timothy and Samuel West, playing the leads.