This chapter describes how the overhead projector develops into a projection tool which first experiences broad cultural acceptance through its use in schools. In the 1960s and 1970s, the first theories of Computer Supported Cooperative Work (CSCW) emerged, promising increased productivity and innovation through research organization in small, interdisciplinary teams. The overhead projector then was regarded as a medium that reinforces interactivity and collective thinking in such small groups via dynamic transparencies, explicitly separated from 35mm slide projection as a medium of organization of a passive crowd of isolated spectators. In the course of digitalization, this idea of organization then turns into its opposite: PowerPoint, originally developed for the production of transparencies for overhead projectors, became a presentation tool through the coupling with projectors, which organizes a passive crowd of spectators in front of static slides like the 35mm slide projection before. A large part of PowerPoint’s epistemological criticism today stems from this form of medial organization.