People have betrayed their country, or their friends, for all kinds of different reasons – and often a traitor to one person is a friend to another, especially as those found guilty of treason have historically faced only one penalty – death. Betrayal for money is perhaps the most despicable level of treachery – not for nothing is the term ‘Judas’ applied with such contempt; others have earned the mark of treason for rebelling against established authority. The stories in ‘Traitors’ range from a British seaman in the Second World War who sold information to the Nazis for a pittance, to the White Rose gang’s defiant campaign against Hitler; from the recusant terrorism of Guy Fawkes, to the abolitionist fury of John Brown; from the unwitting treason of Lady Jane Grey, to the deadly perfidy of Mata Hari.