The BBC Radio 4 programme Desert Island Discs invites castaways to choose eight pieces of music, a book (in addition to the Bible – or a religious text appropriate to that person's beliefs – and the Complete Works of Shakespeare) and a luxury item that they would take to an imaginary desert island, where they will be marooned indefinitely.
The rules state that the chosen luxury item must not be anything animate or indeed anything that enables the castaway to escape from the island, for instance a radio set, sailing yacht or aeroplane.
Very rarely, programmes will be repeated in place of new shows as a tribute to former guests who have recently died – for example Radio 4 repeated Humphrey Lyttelton's show, originally aired on 5 November 2006, on 15 June 2008.
BBC Radio 4 broadcasts new programmes for approximately 42 weeks each year on Sunday mornings, usually with a repeat transmission five days later.
The episodes on BBC Radio 4 Extra have included some 60-minute versions of the show; many of these open with additional lead-in and lead-outs from presenter Kirsty Young, often featuring sections of other interview footage or recordings featuring the guest of the episode in question.