The 120 Days of Sodom, or the School of Libertinage[a] (French: Les 120 Journées de Sodome ou l'école du libertinage) is an unfinished novel by the French writer and nobleman Donatien Alphonse François, Marquis de Sade, written in 1785 and published in 1904 after its manuscript was rediscovered.

It describes the activities of four wealthy libertine Frenchmen who spend four months seeking the ultimate sexual gratification through orgies, sealing themselves in an inaccessible castle in the heart of the Black Forest with 12 accomplices, 20 designated victims and 10 servants.

The stories inspire the libertines to engage in acts of increasing violence leading to the torture and murder of their victims, most of whom are adolescents and young women.

Neil Schaeffer calls it "one of the most radical, one of the most important novels ever written",[2] whereas for Laurence Louis Bongie it is "an unending mire of permuted depravities".

Their main accomplices are four middle-aged women, who have spent their lives in debauchery and will recount stories of libertinage, torture, and murder for the pleasure and instruction of the male libertines, who will then seek to emulate these crimes on selected victims.

[8] The orgy takes place from 1 November to 28 February and is organised according to rules and a strict timetable, to which each of the victims must adhere on pain of corporal punishment or death.

Each storyteller is on duty for a month, and each evening she recounts a story from her life that illustrates five "passions" (perversions of the laws of nature and religion).

The result was a scroll 12 metres (39 ft) long and 12 centimetres (4.7 in) wide that Sade would hide by rolling it tightly and placing it inside his cell wall.

As revolutionary tension grew in Paris, Sade incited a riot among the people gathered outside the Bastille when he shouted to them that the guards were murdering inmates; as a result, two days later on 4 July 1789, he was transferred to the asylum at Charenton, "naked as a worm" and unable to retrieve the novel in progress.

Gérard Lhéritier bought the scroll for his investment company for €7 million, and in 2014 put it on display at his Musée des Lettres et Manuscrits (Museum of Letters and Manuscripts) in Paris.

[19][23][24] The government offered tax benefits to donors to help buy the manuscript for the National Library of France by sponsoring a sum of €4.55 million.

The language of Les Cent Vingt Journées de Sodome is that of a universe which degrades gradually and systematically, which tortures and destroys the totality of the beings which it presents... Nobody, unless he is totally deaf to it, can finish Les Cent Vingt Journées de Sodome without feeling sick.

"[31] In contrast, Melissa Katsoulis, writing in The Times of London, called the novel "a vile and universally offensive catalogue of depravity that goes far beyond kinky sex to the realms of paedophilia, torture and various other stomach-churning activities that we're all probably better off not knowing about.

[34][35] In 1954, Olympia Press in Paris published an English edition translated by Austryn Wainhouse which was not sold openly in English-speaking countries.

According to Phillips, Sade's intention was avowedly pornographic but he also intended the novel as social satire, a parody of the encyclopaedia and the scientific method, a didactic text expounding a theory of libertinage, and a fantasy of total power and sexual licence.

[38] The novel displays typical Sadeian themes including an obsession with categorisation, order and numbers; an alternating presentation of dissertations and orgies; and a desire to catalogue all sexual practices.

[27] Phillips links the novel's emphasis on order, categorisation, numbers and coprophilia with the Freudian anal phase of human sexuality.

[40] Sade biographer Neil Schaeffer sees the main theme in the novel as rebellion against God, authority and sexual gender.