The concept “media thinking” designates an analytical space of the greatest possible openness, a space wherein the disciplinary and programmatic limits of media studies and media art may be expanded in order to enable access to variant-rich fields. The task of the present volume is to illustrate this openness, as it evolved in the early decades of the institutional disciplining of media, by tracing the origin and development of a number of these variants of particular concepts and analyses. The genealogical approach, realized through conversations with media thinking protagonists from German-speaking countries, is of course by no means complete but excerptive; its movement is not retrospective but oriented toward new spaces of possibility for a kind of media thinking to come. The conversations that took place between 2012 and 2014 at the Forum on the Genealogy of Media Thinking, led by Siegfried Zielinski, engaged a wide variety of discourses: from the dominance of linguistics and semiotics, through experimental video activism and performance, to an expanded concept of the image in the field of art; from the cyberneticization of relations, through the philosophy of technology, to information science and other experiments with symbolic machines; from aesthetics, through speculative techno-utopias and net activism, to an expanded hermeneutics of medial artifacts. These conversations were carefully transcribed, edited, annotated and are here supplemented with a bibliographical apparatus and comprehensive index, as well as findings from the private research collections contributed by participants in the Forum.