A 1954 erotic novel by Anne Desclos, written under the pseudonym Pauline Réage. By far one of the most famous, and generally considered the best-written, piece of BDSM pornography. She wrote it to win back her lover, Jean Paulhan. The novel has become a major source of tropes for later BDSM, although most of what Desclos describes existed in previous pornography. (The plot itself is closest to Marquis de Sade's Philosophy In The Bedroom.) Predictably, it was a major target of criticism by the French government, who tried to ban it, and later by (some) feminists, many of whom argued that the book was obviously written by a man. Desclos remained anonymous for four decades, during which time several movie adaptations were made, and someone else even published a sequel under the Pauline Réage pseudonym. She finally came clean in an interview with the New Yorker.
The story is as follows: A photographer known only as O is taken by her lover to a chateau in Roissy, outside Paris. Here she is forced to become one of many sex slaves for a secret society of men, and is routinely beaten. All the same, she finds that she enjoys this role. Released from Roissy back into a version of her everyday life, she is enjoined by her lover to obey a series of rules. As time passes, O's lover asks her to help him in seducing her friend Jacqueline and bringing her to Roissy as well. At the same time, he "gives her" to his stepbrother, Sir Stephen. Stephen, in turn, turns O over to Samois, an all-female environment similar to Roissy, in which she is beaten and eventually pierced and branded. Finally, she agrees to seduce Jacqueline and Jacqueline's younger sister, as well.