The aesthetics of illusion were indeed dismissed towards the end of the 19th century, but at the same time, film reintroduces them through the back door. From there, the aesthetic techniques of illusion are reimported into other arts: new forms of integrating film and video are being experimented with on opera and theater stages, in galleries, and in museums. Against the backdrop of this contemporary aesthetic practice of boundary dissolution, Gertrud Koch's film theory study reveals the fundamental role of film in the aesthetics of illusion and analyzes its techniques using concrete examples from contemporary (music) theater and the visual arts, among others.