Puccini derived the plot of his opera Tosca from a contemporary popular play. The opera describes Baron Scarpia, the villainous chief of police, as “a bigoted satyr who uses devoutness to hide his libertine lust and, to implement his lascivious talent, acts as both confessor and hangman”.This intriguing combination of religiosity and evil has attracted the attention of several writers, notably Susan Sontag and the Italian novelist Paola Capriolo, who in Floria Tosca brilliantly explored the link between pleasure and pain, making Scarpia both torturer and self-styled agent of redemption.Piers Paul Read’s most recent non-fiction book is The Dreyfus Affair; he is best-known for Alive: the story of the Andes survivors, which tells the story of the 1972 air crash and its afte