This chapter uses the distinctive element of modern theatre architecture, the proscenium, as a means to consider the distinctive apparatus of the modern theatre, a machine that locates the actors and the spectators within a technically administered representational economy. From the invention and deployment of gas and then electric lighting in Europe – systematized in Richard Wagner’s Festspielhaus – in the 1860s to the pervasive digitization of sound, lighting, and climate in the modern theatre, the structure of the event of theatre is increasingly understood as a place for the quiet, silent, and darkened consumption of images of action. Drawing on plays from Jackie Sibblies Drury’s Fairview to Luigi Pirandello’s Six Characters in Search of an Author to Thornton Wilder’s Our Town to Samuel Beckett’s Act Without Words I, Play, and Catastrophe, this chapter situates the “black box” of modern theatre alongside the “black box” of modern technologies, as an instrument theatricalizing the human at the interface of input and output.