Radio is magic. In the early twentieth century, this magic was new, revolutionary, and poorly understood. It was the object of scientific investigation, but more importantly, it was also the domain of tinkerers, “hackers”, citizen scientists, and hobbyists. Radio was not only a symbol of modernity, it was also a site where individuals wrestled with and ultimately came to terms with the new and often frightening wave of new technologies and mass medias, which came in the early twentieth century. We need to look back at the time when radio was new to understand how we got to the internet age. This book shows how radio was appropriated and mediated by ordinary individuals in Germany in the first half of the twentieth century as a hobby or leisure-time activity. In particular, it looks at how private associations, clubs, became the locus of this process. Within these clubs, technology, in the form of radio, intersected with the public sphere. This is a much wider process, but the book uses Germany as a case study. Our engagement with technology is always rooted in social structures, institutions, and frameworks. The radio clubs in Germany provided much of the social context within which individuals could come to grips with radio. Without all of this human “packaging” around the basic technology, there could have been no human interaction with it. The introduction sets the stage and discusses some of the eclectic theoretical underpinnings of the book. It also thanks all those who helped.