Marquis de Sade needs no introduction: He was libertine, irreverent, cruel, and, through his deeds and writings, the reason and origin of the term sadism.  "Philosophy in the Bedroom" is a work by Marquis de Sade relatively "light" compared to his other works, such as "The 120 Days of Sodom," for example. Here, the libertine Marquis even indulges in philosophizing about issues like religion and customs amidst one orgy and another. But let the reader not be mistaken: when it comes to Sade, even the slightest is shocking. In "Philosophy in the Bedroom," Madame de Saint-Ange requests a certain banker to send his 15-year-old daughter to her house for a few days so that she can be initiated into the world of libertinism, and what follows are the theoretical and practical lessons taught by a select and devoted group of libertines.