The mad scientist is a popular figure found in horror films from many nations and cultures. Capable of monstrous acts of violence and transgression, these scientists possess a twisted morality, deeming scientific and technological advancement as more important than ethics and empathy for fellow human beings. This chapter will examine the portrayal of the mad scientist in several horror films from Europe through a new approach to analysis of horror, that of Sadean philosophy. By applying the Marquis de Sade’s philosophy of bodily transgression and sexual experimentation to the representation of the mad scientist in European films, we see how the scientist is much like a Sadean libertine, who is constantly exploring the possibilities and limitations of the body and its propensity for both pleasure and pain. This differs from the view, dispensed by scholars who examine primarily Hollywood films as examples, 1 that mad science narratives are cautionary tales that warn against “playing God” and upsetting the natural order. From a Sadean perspective, nature itself is always transgressing and mutating; therefore, the mad scientist is actually following nature as he or she conquers it. Faced with nature’s endless cycle of transgression, the scientist, similarly to the Sadean libertine, manages all of this excess through the enforcement of structure, order, and cold scientific thought. Thus, the mad scientist’s surgical procedures are not that far removed from the libertine’s organized and rule-driven activities, which are enforced to encourage further transgression and experimentation rather than to restore the status quo.