The Marquis de Sade wrote this extraordinary text whilst imprisoned in the Bastille in 1785. It tells the story of four well-heeled libertines who lock themselves and their sexual victims up in a remote medieval castle, having resolved to explore the moral and physical parameters of sexual gratification. Among their victims (a number of whom are children) are four prostitutes, who are called upon to relate the details of their most perverted clients. The action of these stories is closely imitated by the four aristocrats, and includes details of torture, rape and paedophilia.
The novel was not finished, and, somewhat unsurprisingly, possesses a long history of controversy. If such be your taste or curiosity, you can read some of de Sade’s work here. The film Quills (2000) stars Geoffrey Rush as de Sade and explores in colourful if disturbing detail his last years in an asylum for the insane.