A freshly translated critical edition of the infamous eighteenth-century sadist's sprawling work of eroticism that endures today as a serious philosophical argument. The infamous libertine Marquis de Sade (1740-1814), from whose name we derive the word sadism, wove into his pornographic writings many strands of philosophical brilliance whose insights, interspersed between appalling descriptions of sexual deviance, have perplexed readers for centuries. First published in 1795, Philosophy in the Boudoir remains one of the most influential of these works, containing a powerful essay that distills Sade's most illicit ideas into a compelling argument for personal freedom. In it, Sade experiments with forms drawn from sentimental fiction, pornography, philosophical dialogue, and drama to both satirize his contemporaries and champion the virtues of the heroic libertine--an important intellectual precursor to ideas further developed by Nietzsche, Freud, and others. This new critical edition is freshly translated into contemporary English and includes a scholarly introduction and extensive notes that illuminate Sade's myriad allusions and cultural connections, particularly to the larger world of Enlightenment Europe.