 Directors such as Radley Metzger ("Theresa and Isabelle" 1968), Joseph Sarno ("Inga" 1968), and Just Jaeckin ("Emmanuelle" 1974) were influential pioneers of the softcore-romance film.Their "middlebrow sexploitation" movies put stories of female desire at the center, and helped pave the way for softcore's reemergence in the 1990s.Since the erotic thriller is a hybrid of these genres, pinning down the exact formula for an erotic thriller can be difficult.