he was an author. "But if there seems little reason for literary people to concern themselves with Sade, he has found a new lease of life among philosophers and anthropologists. Bored and uneasy with our little lives we resort to the greater amplitude of symbols. Bardot, Byron, Hitler, Hemingway, Monroe, Sade: we do not require our heroes to be subtle, just to be big. Then we can depend on someone to make them subtle." (D.J. Enright in 'The Marquis and the Madame', in Conspirators and Poets, 1966) http://www.kirjasto.sci.fi/desade.htm

Marquis De Sade was the 'inventor' of sadism. Thats where the origin of the word 'sadism' comes from, his surname.

Just adding to what everyone else has said: The last link is a bio. From http://www.answerbag.com/q_view.php/2118 Did Marquis D.A.F. de Sade actually practice all the things he wrote about? Between the excerpts I have perused from his books and his biographical information, I conclude that yes is a safe answer for the most part. However, it is important to note that he wrote many of his works in prison and he spent a considerable amount of his life imprisoned. Did he do every single thing he wrote about? No, I would suppose not. A lot of it. . .yes. Here's a link to a well done and succint biography that discusses his arrests for his numerous debaucheries: http://www.crimelibrary.com/notorious_murders/famous/sade/index_1.html?sect=13

Contrary to another answer he didn't "invent" Sadism- it existed before that- but he did lend his name to the practice of deriving sexual pleasure from inflicting pain. (If you're interested the word "Masochism" derives from Leopold Van Sacher Masoch, another kinky aristocrat author- obviously they'd have made a great couple but as far as I'm aware they never met) He was a French aristocrat who lived in Paris during the time of the French Revolution- he became notorious for his rather unusual sexual tastes- which included anal sex with partners of both sexes, whippings and various other torturous practices as part of his sex life (usually involving prostitutes). He spent a good deal of his life in prison for various "obscenities"- the most notable being obscenity and attempted poisoning when he invited a group of prostitutes back to his room and fed them with cakes laced with Spanish Fly (old-fashioned reputed aphrodisiac) - unfortunately, contrary to his intention, the prostitutes in question became very sick as a result (hence the poisoning charge). He started writing whilst in prison, mainly to pass the time - probably his most famous works are the twin novels "Justine" and "Juliet" which are intended to portray the "Misfortunes of Virtue"- both girls are subjected to a never ending array of sexually orientated punishments throughout the books (for no apparent reason- plotting wasn't really his strong point) Juliette remains the virtuous sufferer, resisting her tortures and retaining her faith, and is seemingly punished all the more for her efforts (at the end of the book she is killed by a bolt of lightning passing through her mouth and out of her vagina- inventive...) whereas Justine welcomes and revels in sexual vice, and appears to prosper. He was briefly released from prison after the storming of the Bastille under the assumption that any enemy of the old regime must be a friend of the new, but was swiftly put back there again, where he continued to write. His books are less well known than his reputation these days - making quite awkward reads, they come across as far more misanthropic than your average pornography, and often fall flat on modern porn fan's sensibilities, and the literary establishment, even once it got over the idea of shunning "obscene" works, now often dismisses his work as repetitive, flat, and devoid of any real merit. If you have the chance his stuff is worth a read though, even if only for the black sense of humour that runs through it. (One story is based solely around a tree whose buds smell of spunk and the embarrasment of servants when asked about it by their young aristocratic charges) Although its not strictly historically accurate you might also want to watch the movie "Quills" which tells part of his story (damn good film too..)